module_basic and organic chem (eng)

LABORATORY GUIDE BOOKBASIC&ORGANIC CHEMISTRY

BASIC CHEMICAL PROCESS LABORATORYDEPARTMENT OF CHEMICAL ENGINEERING

FACULTY OF ENGINEERING UNIVERSITY OF INDONESIA

DEPOK 2013

2

VISION AND MISSION DEPARTMENT OF CHEMICAL ENGINEERING

VISION

“To become a world class Chemical Engineering Department as center of

excellence for education and research in chemical engineering”

MISSION

The Department seeks to provide the best quality of undergraduate and

postgraduate education. The Department will provide a broad-based education

and design experience, enabling students to address chemical engineering

problems. Furthermore, the Department will provide students with fundamental

elements to develop in the profession in response to rapidly chaning technology

and societal needs and expectations, and, will also develop important soft skills

such as problem solving, communication, and group skills.

Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

3

BASIC & ORGANIC CHEMISTRY LABORATORY

EXPERIMENTS:

1. Physical and Chemical Properties

2. Separation and Purification of Substances

3. Reactions of Acids and Bases

4. The Reaction of Metals with Acids

5. Water Crystals

6. Identification of Hydrocarbon

7. Identification of Alcohol

8. Lipid, Oil, Soap, and Detergent

9. Extraction and Identification of Fatty Acids from Corn Oil

10.Properties of Carboxylic Acids and Esters

11.Carbohydrates


4

Laboratory Regulation1. All practitioners must wear white lab jacket during the lab work.

2. All practitioners must be present 10 minutes before the pre-test begins and sign the

presence list.

3. All practitioners must handle Introduction Report and Lab Journal to the assistant

before the lab begins. All journals can be requested again to the assistant after joining

the pre-test.

4. All practitioners must participate the pre-test before the experiment is done until the

responsible assistant have appraised that he is proper and able to do the given

experiment module. If the practitioners do not join the pre-test, the experiment is

stated as null and void. The pre-test is taken place for 10 to 20 minutes.

5. All practitioners must make a note of all observation results from the experiment that

should be done in the Lab Journal. In the end of the experiment, all the observation

results must be known and signed by the assistant.

6. The lab work report must be completed in a week after the lab work to the assistant.

Delayed report will be given punishment and they will not to be allowed to join the

lab work at transfer of the lab work report.

7. The lab work report that has not fulfilled the requirements must be fixed and handled

to the assistant in a week after it has been stated as a need to be fixed.

8. Borrowing the devices of the lab work must be permitted by the laboratory’s

employee and returned them in the same condition.

9. Before leaving the laboratory, practitioners must clean the desk and the equipment;

also put in order the material and the equipment.

10. The use of the equipment and chemical material must be careful, do not spill it.

11. Damage of the castaway equipment/material that happens because of working error

and practitioner’s negligence must be substituted by the practitioner with the same

equipment/material.

12. Be well mannered to the laboratory’s employee and the assistant.

13. The absence of practitioners on the scheduled date will get punishment, and will be

considered as null and void, except there is an acceptable reason e.g. unavoidable

calamity.


5

14. The absence caused by sickness, the experiment can be done with the assistant’s

agreement beyond the lab work’s schedule, after having the permission from the Lab

work’s University coordinator. The dispensation of rescheduling that is caused by

sickness only permitted once during the lab work’s period.

15. The requirements to pass the lab subject:

Have participated in a pre-test and handled the Introduction Report and Journal

before the lab work’s begun.

Have performed all experiments in the same semester and stated as Pass by the

assistant.

Handle the lab work’s report for all of the experiments that have been done and

scored by the assistant.

Pass the final test of the lab work.


6

Laboratory Report Format

I. PRE-REPORT AND JOURNALWRITING

DATEEXPERIMENT 1

TITLE

I. OBJECTIVEII. LAB WORK PRINCIPLEIII. EQUIPMENT AND CHEMICALSIV. PROCEDURE AND OBSERVATION

EXPERIMENT LAB WORK PROCEDURE OBSERVATION RESULT

A

1.2.3.4.

B

1.2.3.4.

Laboratories : Name/NPM : 1. ……….

2. ……….

Signature of Laboratory Assistant

( )


7

II. LAB REPORTWRITING

II.1. COVER

ORGANIC CHEMISTRY LAB REPORTEVEN/ODD SEMESTER 201…/201…

GROUPNAME : 1.

2.NPM : 1.

2.

BASIC CHEMICAL PROCESS LABORATORYDEPARTMENT OF CHEMICAL ENGINEERING

FACULTY OF ENGINEERINGUNIVERSITAS INDONESIA

DEPOK 201…

II.2. CONTENT

DATEEXPERIMENT 1

TITLE

I. THEORYII. DATA PROCESSINGIII. OBSERVATION RESULT ANALYSISIV. ASSIGNMENT AND QUESTION ANSWERV. REFERENCE

GROUP :1. ………………….NPM ……………….2. ………………….NPM ……………….

Signature of Laboratory Assistant

( )


8

Common Procedures and Concept

To get an accurate result during the experiment, it is important to know the basic

principle related with laboratory equipment utilization.

I. Heating

Most of heating process in laboratory are done with gas burner. For some cases, we

will use oven equipment during this process. Bunsen burner (from the figure below) usually

has 2 valves for gas and air arrangement.

To turn on a bunsen burner, please follow these steps:

Air valve is in a closed condition,while the gas valve is in an opened condition

Turn it on with matches. From this step, we will see a not-too-hot red flame

To get a better flame and higher temperature from the bunsen burner, open the air valve

slowly until the blue flame appear.

After combustion, turn off the bunsen burner by closing the gas flow.

If the bunsen burner is used for heating a substance in a beaker glass / test-tube , the

steps can be seen from this figure below:

Attention! Don’t aim the mouth tube to another people’s face!


Heating or burning process for components inside the reaction tube.

Heating process of Baker glass using Bunsen burner.

9

II. Filtration

Filtration aims to separate a liquid substrate from the solids one by passing the

substrate through a filter paper. The filtration procedure is as follows:

Fold the filter paper like the figure below:

Set it on the funnel, then wet the filter paper with distilled water and avoid any air cavity

behind the filter paper.

Note that the position of the filter paper must 0.5-1 cm from the top edge of

the funnel and the amount of sediment is 2/3 from the maximum height of the

filter paper.

Set the funnel in the buffer reservoir dan put the vessel under it.


10

Pour the liquid substrate through a stirring rod carefully.

Rinse several times with distilled water until completely clean

III. Scale Reading

In a fluid-volume measuring equipment, contained circular lines mark which

indicating the height of limit on the volume of fluid given. As the boundary surface reading is

part of curved liquid, except for liquid whose color is dark, read at the top of the curved

surface of the liquid. More details can be seen in the figure below:

IV. Washing Equipment

All of the equipements used in chemical laboratory must in a clean condition. The

clean equipment can be known when if the surface wetted, there will be a new layer of

distributed liquid. The prescense of fat or dust will cause uneven coating distribution.

Washing/cleaning equipment is done by washing it with detergen , scrubbed it with a

brush if necessary, then rinse it with distillate water. To wash the equipment which is very dirty,

it is important to use potassium dichromate solution in sulfuric acid. How to make the solution

can be asked to the assistant.


11

Experiment 1PHYSICAL AND CHEMICAL

PROPERTIES

I. OBJECTIVES

Distinguishing physical and chemical properties of a substance.

II. INTRODUCTION

Aaaaaaaaaa

III. EQUIPMENT & CHEMICALS

III.1. Equipment

1. Bunsen

2. Test tube clamp

3. Rubber suction

4. Measuring cylinder 10 ml

5. Ni-Cr wire

6. Test tube

7. Graduated/Measuring pipette

8. Funnel

9. Beaker glass 100 ml

10. Washing bottle & Pipette

III.2. Chemicals

1. Zinc (Zn)

2. Copper (Cu)

3. Magnesium (Mg)

4. Iron (Fe)

5. Aluminum(Al)

6. Calcium carbonate (CaCO3)

7. Cupric nitrate (Cu(N03)2)

8. Calcium hydroxide (KOH)

9. Concentrated sulfuric acid (concentrated H2SO4)Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

12

10. Sodium hydroxide solution (NaOH solution)

11. Acetic acid (CH3COOH)

12. Calcium hydroxide (Ca(OH)2)

13. Hydrochloric acid (HCl)

14. Salt/sugar

15. Methanol/benzene/toluene/ether

16. Wood

17. Calcium carbonate/CaCO3

18. Distillated watert

IV. PROCEDURES

IV.1. Physical Properties

1. Observe and record the shape, color, and smell of the following substances: Methanol,

CaCO3, sugar, Toluene, Benzene, HCl and NaOH.

2. Dissolve each substance in the water. Shake the solution, observe and record the

changes.

3. Do the step number 2 to ether.

4. Explain how to identify substances that have the same shape and color, based on

the physical properties of these substances.

IV.2. Chemical Properties

A. Changes caused by base effect

1. Insert a piece of Al, Zn, Fe and CaCO3 into different test tubes.

2. Add 5 ml of dilute NaOH to each tube. Note the change.

B. Changes caused by acid effect

1. Insert a piece of Cu, Zn, CaCO3 and KOH into different test tubes. Add 3 ml of dilute

HCl to each tubes. Note the change and write the equation of reaction.

2. Pour concentrated H2SO4 into a test tube then insert a piece of wood into it. Note the

change.


13

C. Changes caused by heat effect

By using the test tube clamp, heat a piece of magnesium in a bunsen flame. Repeat

this experiment with Cu loops. Note the event that happen.

V. POTENTIAL HAZARDS

aa

VI. REPORT FORMAT

Aa


14

Experiment 2SEPARATION AND PURIFICATION OF

SUBSTANCES

I. OBJECTIVES

To know the types of separation based on the physical and chemical properties.

II. INTRODUCTION

Mixtures are not unique to chemistry; we use and consume them on a daily basis. The

beverages we drink each morning, the fuel we use in our automobiles, and the ground we

walk on are mixtures. Very few materials we encounter are pure. Any material made up of

two or more substances that are not chemically combined is a mixture.

The isolation of pure components of a mixture requires the separation of one

component from another. Chemists have developed techniques for doing this. These methods

take advantage of the differences in physical properties of the components. The techniques to

be demonstrated in this laboratory are the following:

1. Sublimation. This involves heating a solid until it passes directly from the solid phase

into the gaseous phase. The reverse process, when the vapor goes back to the solid phase

without a liquid state in between, is called condensation or deposition. Some solids

which sublime are iodine, caffeine, and paradichlorobenzene (mothballs).

2. Extraction. This uses a solvent to selectively dissolve one component of the solid

mixture. With this technique, a soluble solid can be separated from an insoluble solid.

3. Decantation. This separates a liquid from an insoluble solid sediment by carefully

pouring the liquid from the solid without disturbing the solid (Figure 2.1).

4. Filtration. This separates a solid from a liquid through the use of a porous material as a

filter. Paper, charcoal, or sand can serve as a filter. These materials allow the liquid to

pass through but not the solid (see Figure 2.2 in the Procedure section).

5. Evaporation. This is the process of heating a mixture in order to drive off, in the form of

vapor, a volatile liquid, so as to make the remaining component dry.


15

Figure 2.1. Decantation

Figure 2.2. Separation scheme


16


III.1.Equipment

1. Test tube

2. Filter paper

3. Vaporizer bowl

4. Mixer

5. Drop straw

6. Measurement glass 10 ml or 25 ml

7. Wash bottle

8. Bunsen

9. Funnel

10. Watch glass

11. Beaker glass

12. Scale

13. Ni-Cr wire

14. Clamp

III.2. Chemicals

1. KNO3

2. Na2SO4

3. Sodium Cobalt Nitrite

4. Al(OH)3

5. KOH 2 M

6. KCNS

7. Cu(NO3)2

8. NH4Cl

9. BaCl2

10. Fe2O3

11. Dilute HCl

12. Distillated water


17

IV. PROCEDURES

IV.1. Separation of substance based on physical properties

IV.1.1. Dissolution and Filtration

The purification or separation mixtures of solid substances and solid substances based

on the solubility difference in substance of a particular solvent.

1. Make a mixture substance with salt and lime with the weight ratio isdetermined by the

assistant (%wt)

2. Weigh the mass of filter paper

3. Dissolute that mixture substance into warm water (200 cc), then write down the

temperature of water, and stir it until the substances dissolve completely.

4. Filter the substance that not soluble, then drying it and weigh it

5. Calculate the mass percent of the salt that can separated before.Give a comment from

your results of observation!

IV.2.2.Crystallization

The separation substance based on the solubility and temperature difference from two

or more of substances.

1. Add 10 ml of distillated water into test tube, then adding KNO3 2 M 3 ml into that test

tube with little CuNO3 (1 spatula). Heating that mixture until soluble, then cooling it

and filtering the crystal that form. Rinsing it with distillated wateruntil the color

disappears.

2. Dissolve a little crystal into the distillated waterand testing ion K with ion specific

test. To another crystal, we do flame test.

IV.1.3. Sublimation

The separation of substances that have a high pressure on temperature basis below the

melting point.

1. Put a mixture of Na2SO4 and NH4Cl (2 grams each) into vaporizer bowl. Heating it

slowly until white steam appears. Put watch glass on bowl, and continuing the heating

until there are no white steam.

2. Collect the white substances that cling on watch glass, then add 10 ml of water. White

substances is divided into 2 parts :


18

a. The part where NaCo(NO2)6 is added (sodium cobalt nitrite). Observed and write

down that occurs!

b. The part where BaCl2 is added (Barium Chloride). Observed and write down that

occurs!

IV.2. Separation of substance based on chemical properties

Separation based on amphoteric substance

1. Weigh Al(OH)3 and Fe2O3 (1 grams each)

2. Put the mixture substance into beaker glass 250 ml, adding 15 ml of water and 25 ml

of KOH 2 M, then heat up the solution and stir the solvent until Al(OH)3 soluble.

3. Cool the solution and filtering it. Dissolve the sediment into HCl dilute and test it with

KCNS. Observe what that happen!

4. Add dilute HCl with drop by drop wise into the filtrate. Observe what that happen!


aa

VI. QUESTIONS AND PROBLEMS

1. Explain and write down the reaction of sublimation!

2. Determine the percipates that occurs in the above experiment!

VII. REPORT FORMAT

aaaa


19

Experiment3REACTIONS OF ACIDS AND BASES

I. OBJECTIVES

1. To identicifate acids and bases by investigate the pH of some solutions

2. To know the influence of concentration to the solutions’ pH

3. To calculate the concentration and the stochiometry of acids and bases

II.INTRODUCTION

We frequently encounter acids and bases in our daily life. Fruits, such as oranges,

apples, etc., contain acids. Household ammonia, a cleaning agent, and Liquid Plumber are

bases. Acids are compounds that can donate a proton (hydrogen ion). Bases are compounds

that can accept a proton. This classification system was proposed simultaneously by Johannes

Brønsted and Thomas Lowry in 1923, and it is known as the Brønsted-Lowry theory. Thus

any proton donor is an acid, and a proton acceptor is a base.

When HCl reacts with water

HCl + H 2 O⇄ H 3O+¿ ¿ + Cl−¿¿

HCl is an acid and H 2 O is a base because HCl donated a proton thereby becoming Cl−¿¿,

and water accepted a proton thereby becoming H 3 O+¿¿. In the reverse reaction (from right to left)

the H 3 O+¿¿is an acid and Cl−¿¿is a base. As the arrow indicates, the equilibrium in this reaction lies

far to the right. That is, out of every 1000 HCl molecules dissolved in water, 990 are converted to

Cl−¿¿and only 10 remain in the form of HCl at equilibrium. But H 3 O+¿¿ (hydronium ion) is also an

acid and can donate a proton to the base, Cl−¿¿. Why do hydronium ions not give up protons to Cl−¿¿

with equal ease and form more HCl? This is because different acids and bases have different

strengths. HCl is a stronger acid than hydronium ion, and water is a stronger base than Cl−¿¿.

In the Brønsted-Lowry theory, every acid–base reaction creates its conjugate acid–base pair.

In the above reaction HCl is an acid which, after giving up a proton,becomes a conjugate base, Cl−¿¿.

Similarly, water is a base which, after accepting a proton,becomes a conjugate acid, the hydronium

ion.


20

Some acids can give up only one proton. These are monoprotic acids. Examples are

HCl, HNO3, HCOOH , and C H 3 COOH . The hydrogens circled are the ones donated. Other

acids yield two or three protons. These are called diprotic or triprotic acids. Examples are

H 2 SO4, H 2 CO3, and H 3 PO 4. However, in the Brønsted-Lowry theory, each acid is

considered monoprotic, and a diprotic acid (such as carbonic acid) donates its protons in two

distinct steps:

1. H 2 CO3 + H 2 O⇄ H 3O+¿ ¿ + HCO3

−¿ ¿

2. HCO3−¿+H 2 O⇄H 3 O+¿+CO 3

2−¿¿¿ ¿

Thus the compound HCO3−¿ ¿

is a conjugate base in the first reaction and an acid in

the second reaction. A compound that can act either as an acid or a base is called

amphiprotic. In the self-ionization reaction

H 2 O+H 2O⇄H 3 O+¿+OH−¿¿ ¿

one water acts as an acid (proton donor) and the other as a base (proton acceptor). In

pure water, the equilibrium lies far to the left, that is, only very few hydronium and hydroxyl

ions are formed. In fact, only 1 x10−7moles of hydronium ion and 1 x10−7moles of hydroxide

ion are found in one liter of water. The dissociation constant for the selfionization of water is

This can be rewritten as

Kw, the ion product of water, is still a constant because very few water molecules

reacted to yield hydronium and hydroxide ions; hence the concentration of water essentially

remained constant. At room temperature, the Kw has the value of

Kw=1 x 10−14=[1 x10−7 ] x ¿

This value of the ion product of water applies not only to pure water but to any

aqueous (water) solution. This is very convenient because if we know the concentration of

the hydronium ion, we automatically know the concentration of the hydroxide ion and vice


21

versa. For example, if in a 0.01 M HCl solution HCl dissociates completely, the hydronium

ion concentration is ¿This means that the ¿¿ is

¿¿

To measure the strength of an aqueous acidic or basic solution, P. L. Sorensenintroduced the

pH scale.

pH=−log¿¿

In pure water, we have seen that the hydronium ion concentration is 1 x10−7M. The

logarithm of this is -7 and, thus, the pH of pure water is 7. Since water is an amphiprotic

compound, pH 7 means a neutral solution. On the other hand, in a 0.01 M HCl solution

(dissociating completely), we have ¿ Thus its pH is 2. The pH scale shows that acidic

solutions have a pH less than 7 and basic solutions have a pH greater than 7.

The pH of a solution can be measured conveniently by special instruments called pH

meters. All that must be done is to insert the electrodes of the pH meter into the

solution to be measured and read the pH from a scale. pH of a solution can also be obtained,

although less precisely, by using a pH indicator paper. The paper is impregnated with organic

compounds that change their color at different pH values. The color shown by the paper is

then compared with a color chart provided by the manufacturer.

There are certain solutions that resist a change in the pH even when we add to them

acids or bases. Such systems are called buffers. A mixture of a weak acid and its conjugate

base usually forms a good buffer system. An example is carbonic acid, which is the most

important buffer in our blood and maintains it close to pH 7.4. Buffers resist large changes in

pH because of the Le Chatelier principle governing equilibrium conditions. In the carbonic

acid–bicarbonate (weak acid–conjugate base) buffer system,

H 2 CO3 + H 2 O⇄ H 3O+¿ ¿ + HCO3

−¿ ¿

any addition of an acid,H 3 O+¿¿, will shift the equilibrium to the left. Thus this reduces

the hydronium ion concentration, returning it to the initial value so that it stays constant;

hence the change in pH is small. If a base, OH−¿¿, is added to such a buffer system, it will

react with the H 3 O+¿¿ of the buffer. But the equilibrium then shifts to the right, replacing the

reacted hydronium ions, hence again, the change in pH is small.

Buffers stabilize a solution at a certain pH. This depends on the nature of the buffer

and its concentration. For example, the carbonic acid–bicarbonate system has a pH of 6.37


22

when the two ingredients are at equimolar concentration. A change in the concentration of the

carbonic acid relative to its conjugate base can shift the pH of the buffer. The Henderson-

Hasselbalch equation below gives the relationship between pH and concentration.

pH=pKa+ log¿¿¿¿

In this equation the pKa is the −log Ka, where Ka is the dissociation constant of

carbonic acid

[ HA ] is the concentration of the acid and ¿¿ is the concentration of the conjugate

base. The pKa of the carbonic acid–bicarbonate system is 6.37. When equimolar conditions

exist, then [ HA ]=¿¿ In this case, the second term in the Henderson-Hasselbalch equation is

zero. This is so because ¿¿¿, and the log 1=0. Thus at equimolar concentration of the acid–

conjugate base, the pH of the buffer equals the pKa; in the carbonic acid–bicarbonate system

this is 6.37. If, however, we have ten times more bicarbonate than carbonic acid, ¿¿¿, then

log 10=1 and the pH of the buffer will be


III.1. Equipment

1. 6 test tubes and it’s shelf

2. Burette, stand with utility clamp

3. Pipette, volumetric pipette, and graduated pipette

4. Volumetric flask 100 ml

5. Erlenmeyer 250 ml, beaker glass, glass stirring

6. pH paper/pH universal

III.2. Chemicals

1. Some acids and bases, weak and strong

2. Acids: HCl, HNO3, CH3COOH

3. Bases: NaOH, BaOH2, Mg(OH)2 (or other bases)

4. Indicator phenolphthalein

5. Crystal NaOHBasic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

23

IV. PROCEDURES

IV.1.The Properties of Acids and Bases

1. Ask you assistant to give you 6 acids and bases. Observe and note the color of the

solutions.

3. Take 5 ml of the solution into the test tube. Sign each solution with name L1 until L6.

4. Take the pH paper, dip the edge into the solution. Be careful mot to hit your fingers.

Dry the paper and note the color. Determine the pH of the solution by matching the

color of the pH paper with the instructions in the pH paper’s box.

5. Do the step A3 for all of the solutions given by the assistant. Note all of the solutions’

pH and give sign what solutions are acids and bases. Give basic description of what

you use to distinguish acids and bases.

6. Take one of the acids and bases solution above. Fill into the test tube of each solution 5

ml. Give the sign a0 (acid) and b0 (bases). Perform a ratio of 1:1; 1:10; 1:100; and

1:1000 dilutions. Give the name of each solution a1 until a4 for acids and b1 until b4 for

bases.

7. Measure the pH of each solution as step A2. Record the pH and fill the record into

table accordance with the order of the concentration of the solution.

8. Create a graph of the concentration and pH of the solution. What conclusion that you

get from the experiment?

IV.2. Acids and Bases Reaction

1. Make a solution of 0.1 molar NaOH, HCland acetic acid as 100 ml each. Write the

calculation and how to make the solutions.

2. By using volumetric pipette, take 5 ml of 0,1 molar solution of HCl and put into

Erlenmeyer. Then give 1-2 drops of phenolphthalein indicator. Observe and record the

color.

3. Fill NaOH solution into the burette and record the volume. Read the scale of the

burette correctly.

4. Perform titration of HCl solution by adding a little NaOH and whipped it at each

addition. Stop the addition ofNaOH right at the time of the change of the solution’s

color. Record the volume of NaOH remaining in the burette.


24

5. Write the acid-base reaction. Calculate the number of moles ofHClaccording to

titration’s data and compare the results with theoretical calculation (from the initial

concentration and volume of HCl).

6. Repeat the step 2 to 5 for acetic acid solution.


aa


1. What is the indicator of the acid-base titration? Explain how to select an indicator for

titration.

2. What is the difference of acids/bases strong and weak? Mention the ways to identify

whether an acid and base is strong or weak.

VII. REPORT FORMAT

aa


25

Experiment4THE REACTION OF METALS WITH

ACIDS

I. OBJECTIVES

1. Qualitative and quantitative analysis related with reactivity reaction between metals

and acid.

2. The used of data titration for stoichiometric reaction calculation.

II. INTRODUCTION

II.1. Reactions of acids with metals

Acids react with most metals and a salt is produced. But unlike the reaction between

acids and bases we don't get any water. Instead we get hydrogen gas.

This is the general word equation for the reaction:

metal + acid → salt + hydrogen

II.2. Salts

The salt produced depends upon the metal and the acid. Here are two examples:

zinc + sulphuric acid → zinc sulphate + hydrogen

magnesium + hydrochloric acid → magnesium chloride + hydrogen

It doesn't matter which metal or acid is used, if there is a reaction we always get

hydrogen gas as well as the salt.

II.3.The test for hydrogen

There is a simple laboratory test to see if a gas is hydrogen. A lighted wooden splint

goes pop if it is put into a test tube of hydrogen. This is because the flame ignites the

hydrogen, which burns explosively to make a loud sound.

II.4. Acids and hydrogen

All acids contain hydrogen atoms. Apart from hydrochloric acid, this is not clear from

their names, but you can tell they contain hydrogen from their chemical formulae. Remember

that the chemical symbol for hydrogen is H.


26


III.1.Equipment

1. Glass funnel and filter paper

2. Five test tubes

3. Five erlenmeyer flask 100ml and watch glass

4. Burette, clamp, and balance

5. Pipette, Volumetric pipette, and measuring cylinder

6. Volumentric flask 50 ml

III.2. Chemicals

1. Metal powder Zn (zinc), Cu (copper), Fe (iron) and Al (aluminum)

2. 6 M HCI andNaOH solution

3. Methyl orangeindicator

IV. PROCEDURES

IV.1. Qualitative Observation

1. Provide 4 pieces of test tubes, and fill each tube with 6M HCl solution 5ml. Label it

S1 s/d S4.

2. Weigh each 0,1 gr metals Zn, Fe, Cu and Al. Then, insert those metals to the

test tubes Sl s/d S4. Observe and note the changes happened.

3. If the metals reactivity can be seen from the amount of gas formed, order the metals

reactivity based on your observation!

4. Write down the reaction equation from this experiment and suggest an experiment to test

what kind of gas formed on the reaction above.

IV.2. Quantitative Observation

1. Provide 5 pieces of clean erlenmeyer flask 100 ml. Label itSl s/d S5.

2. Fill each erlenmeyer with 6M HCl 10 ml (use volumetric pipette 10ml, measure it

correctly), then close it with watch glass. Calculate the mole of HCl, and write down

the aswer.

3. Insert Zn, Fe, Cu and Al metals 0,2 gr each into erlenmeyer S1 s/d S4 . Solution in

erlenmeyer S5 will be reacted with nothing.

4. Note when the metals reacted, and let the reaction happened for 30-40 minutes.

(determined by the assistant).


27

5. After the reaction finish, separate the metals from the solution with the filtration process (wet

the filter paper with distillated watert before use it in filtration process).

6. Take the solution from erlenmeyer Sl s/d S5 2 ml each, and add 1-2 drops of methyl

orangeindicator. Observe and write down the color.

7. Titrate the solution with 1.0 M NaOH solution. Calculate the total amount of mole

HCl after reaction.

8. Calculate the HCl conversion with the formula below:

( Amount of mole HCl reacted )( Amount of mole HCl before the reaction)

× 100 %

9. Make a table/graph between the type of metals vs %-HCl conversion. Order the

metals based on their reactivity, and compare this result with the result from

experiment A.


aaa


1. Is there any effect from the location of these metals in periodic table and their

reactivity to react with acid? Explain!

2. What factor affect the rate of reaction in general as long as you know?

VI. REPORT FORMAT

aaaa


28

Experiment5WATER CRYSTALS

I. OBJECTIVES

1. To learn dehidration activity and hidration of a solid containing water crystals.

2. To calculate the empiric formula of water crystals.

II. INTRODUCTION

aaa


III.1. Equipment

1. Threepyrextest tubes

2. Droplet pipette and wood clamp

3. Three vaporazer cup

4. Bunsen burner

III.2. Chemicals

1. Solid materials containing water crystals:CuSO4.XH2O,

MgSO4.XH2O,CaCl2.XH2O.

2. Distillated water

IV. PROCEDURES

IV.1. Qualitative Observation

1. Ask a assistant 3 kinds of solid materials containing crystalline water. Observe and

write down the name of the substance and their colors.

2. Insert those substance into a pyrex test tube each. Label it.

3. Use a wood clamp to hold the test tube, then heat the substance in the tube on the

bunsen burner. Observe and write down the changes happened.

4. Then, drop a water into the test tube. Obseve and write down the changes

happened.

5. Write down the reaction equation, all of the heating and watter addition activity.

Explain those equation and the difference between those substance based on your


29

observation.

IV.2. Quantitavie Observation

1. Provide3 piecesof ceramicbowls(evaporator. Weighand write down

theweightcarefully.

2. Insert solids substance containing crystalline water into the third cup, and write down

the weight. Determine the weight of the substance

3. Heat the cup containing sample until they change color just as color samples of

uniform / homogeneous (color sample has changed all of the colors before

warming),stop heating and immidiately weigh carefully weighed.

4. Calculate the weight loss after heating. If weight loss is showing the amount of water

contained in the crystal sample, determine the empiric formula of crystal water, then

compare with the theoritical and empiric formula.

5. Try this experiment for three different sample and show the similiarities and

differences of your observations


aaa


1. Write down the name, empiric formula, color, and physical properties from 3 kind

of solid substance containing crystal water.

2. Give an example in chemical engineering industries which use dehydration and

hydration process.

VI. REPORT FORMAT

aaaa


30

Experiment 6IDENTIFICATION OF HYDROCARBON

I. OBJECTIVES

To identify several properties of hydrocarbon.

II. INTRODUCTION

Numerous numbers of organic compounds is made by the carbon atoms which attract

one another and other molecule that are able to make bond with known carbon group. To

make it simple, we can say that hydrocarbon is a compound with bond between hydrogen and

carbon only.

Hydrocarbon has many bonds, but can be grouped by their unique characters where

these structures are also suit with the general chemical reactivity. Then every group can be

grouped from its structure or reactivity. In this test, practitioner will test the chemical

reactivity from saturated, unsaturated, and aromatic hydrocarbon.

II.1. Hydrocarbon Structure

Hydrocarbon can be considered saturated if there is maximum number of hydrogen

which is bonded to carbon. It is happen if the carbons bonded as single bond or it is called as

sigma bond (σ). Ethane is an example for saturated hydrocarbon with these criteria.

Unsaturated hydrocarbon has less number of hydrogen which can make bond from its

maximum number. This compound must have double bond so that the total number of

covalent bond is four. Ethylene and acetylene are examples for this compound.


31

Double carbon bonds from ethylene consist of one σ bond which is the same with

saturated hydrocarbon and one pi bond (π). Both of them can form double bond, while

acetylene has triple bond with one σ bond and two π bonds.

Aromatic hydrocarbon has unique bond within its carbon which is difficult to explain.

In benzene, one of aromatic hydrocarbon, all of the carbon bonds are identical (six bonds).

Two type of benzene bonds, a and b, have single and double bonds which are varied.

But, both of them represent a different molecule. Structure (c), using circle inside the

hexagon, can be accepted. The circle represents the six electrons which are distributed evenly

at the aromatic π bond at six carbon atoms. The bonds which are represented by the

hexagonal side are σ bond. Structure (c) can be used to represent all kind of carbon bonds

inside the benzene correctly.

II.2. Reactivity of Hydrocarbon

The σ bond from saturated bond (alkane) is very stable so it is not reactive. At high

temperature, saturated hydrocarbon can react with oxygen (combustion). From this reaction,

carbon bonds are broken and the products are carbon dioxide and water. If the combustion is

not efficient, then carbon monoxide or even single carbon (soot) can be produced. But,

generally, saturated hydrocarbon is combusted more efficiently than other types of

hydrocarbon.

The hydrogen-carbon bond from alkane can be replaced by halogen. General reaction

for bromine is:

Look at the equation, HBr is a product from the reaction. To react with halogen, we

need heat or light energy.

The π bond from unsaturated hydrocarbon (alkene and alkyne) is reactive and it is

easier for additional reaction to happen. In this reaction, a molecule like bromine forms two

single bonds of carbon-bromine which is in one π bond energy level. Ethylene reacts with

bromine to form 1,2-dibromothane.


32

This reaction happens in room temperature. As the product, a character of brownish

red from bromine is disappeared. We should also pay attention to the reaction that there is no

HBr produced like in the substitution reaction for saturated hydrocarbon. Acetylene has two π

bonds which occur additional reaction:

The π bond from aromatic compound is hold out in the reaction. Even for saturated

group which make bond with benzene ring can be attacked by oxidizing agents with a very

large energy. The product which is produced when single group alkyl bonded with benzene

ring is benzoic acid.

Hydrogen atom from benzene can be substituted by bromine, but it needs catalyst Fe.

Look that the following reaction is a substitution reaction and HBr is produced.


33


III.1. Equipment

1. Testtube 10 x 75 mm

2. Testtube 16 x 150 mm

3. Generator acetylene

4. Pipette

5. Watch glass

6. Test tube rack

III.2. Chemicals

1. Heptane

2. Octene

3. Toluene

4. Xylene

5. Butanol

6. Carbon tetrachloride

7. 1% vol bromine in carbon tetrachloride

8. Iron tack

9. 1% wt potassium permanganate solution

10. Unknown sample

11. Calcium carbide

12. Litmus paper

IV. PROCEDURES

Caution: all organic waste must be thrown at the right place.

Note:

5. Do all the following experiments below.

6. Experiment A until D use three types of hydrocarbon: heptane, 1-octene, and toluene.

Use clean and dry test tubes for all reactions. The structure for the three compounds

are :


34

7. Most alkanes contain alkene as pollutant. To clean the pollutant, alkane is mixed with

H2SO4 with the ratio alkane: H2SO4 = 3:1. It will form a layer, where the lower layer

which is darker (H2SO4) is separated. The remaining alkane layer is treated again with

H2SO4 until it do not form anymore darker layer. Then, alkane is washed by water. (be

careful with H2SO4 solution, can be performed only by expert).

IV.1. Solubility of Hydrocarbon

1. Shake slowly the 0.5 mL heptane with 5 mL water solvent in test tube 16x150 mm to

test its solubility. Write down your observation.

2. Repeat step 1 with other samples: 1-Octene and toluene, each with same ratio.

3. Change the solvent with 1-butanol and ligroin (mix of alkane), repeat step 1 and step

2 with same ratio.

IV.2. Flammability of Hydrocarbon

Attention: Hydrocarbon is highly flammable, and its vapor is very explosive in air. Be

careful with the flame. Do not add the quantity of the hydrocarbon as it has already been set

in this experiment.

1. Expel three drops of one type of hydrocarbon sample on the watch glass, by using

matches/lighter, light the hydrocarbon.

2. Observe the type and color of the flame, carbon in the flame and the remaining

residue.

3. Repeat the above steps for other two hydrocarbons.

4. Write down your observation.

IV.3. Effect of Bromine in Carbon Tetrachloride

1. Put 1 mL bromine in carbon tetrachloride in a small test tube.

2. Add 10-20 drops of hydrocarbon sample, observe the change of colour.

3. If there is no colour change after 20 drops, add iron tack, and wait for 5 minutes.

4. If there is still no colour change, heat the solution in a hot water bath for 15-20

minutes.

5. To test if there is hydrogen bromide, place blue litmus paper at the tip of the test tube.

6. Repeat the experiment with two other sample of hydrocarbon.


IV.4. Reaction with Potassium Permanganate

1. Place 1 mL sample of hydrocarbon in a small test tube.


35

2. Add 3 drops of 1% potassium permanganate solution.

3. Shake the test tube, observe all the changes that happen. How long does it need for the

changes to start?

4. Repeat with another sample of hydrocarbon.


IV.5. Grouping The Substance

1. Get unknown samples from your laboratory assistant.

2. Do the tests to group the samples to saturated, unsaturated, and aromatic.

IV.6. Preparation and Chemical Properties of Acetylene

1. Pay attention to the instrumentation of acetylene consists of a dry 250 mL bottle with

two rubber stopper, a dropping line, glass tubing, and appropriate rubber.

2. Put some pieces of calcium carbide (CaC2) inside the dry bottle.

3. Add the water carefully and slowly to a certain degree to form acetylene gas.

4. To dry the test tube 16x150 mm with 10 drops of 1% bromine in carbon tetrachloride

solution, add about 3 mL carbon tetrachloride. Flow the acetylene to the solution.

Observe the changes that happen.

5. For the 16x150 mm test tube which has 3 drops of 1% potassium permanganate, add

about 3 mL water. Flow the acetylene to the solution until the colour of permanganate

is disappeared. If the reaction is slow, shake and continue the flow of acetylene.

Repeat until the colour disappears. Observe the changes that happen.



Flame risk from heating chemical. Use gloves when heating the chemicals with

Bunsen or with water bath.

Heptane

- Breathing vapors may cause drowsiness and dizziness. Causes eye, skin, and

respiratory tract irritation. Aspiration hazard if swallowed. Can enter lungs and

cause damage. Dangerous for the environment.

- Wear protective gloves,clothing and masker to prevent exposure.

1-octene


36

- Causes eye, skin, and respiratory tract irritation. Toxic to aquatic organisms, may

cause long-term adverse effects in the aquatic environment. Aspiration hazard if

swallowed. Can enter lungs and cause damage. May cause central nervous system

effects.

- Wear protective eyeglass, gloves,clothing to prevent exposure.

Toluene

- Causes eye irritation. Prolonged or repeated contact can defat the skin and lead to

irritation and/or dermatitis. Inhalation causes headaches, dizziness, drowsiness,

nausea, and respiratory irritation. If swallowed, causes headaches, dizziness,

drowsiness and nausea, and may lead to unconsciousness. Harmful or fatal if liquid

is aspirated into lungs. Danger! Contains Benzene. Cancer hazard. Can cause blood

disorders. Harmful when absorbed through the skin.

- Wear chemical goggles, protective gloves, and clothing to prevent exposure.

Xylene

- Hazardous in case of skin contact (irritant, permeator), of eye contact (irritant), of

ingestion, of inhalation.

- Wear splash goggles, lab coat, and gloves.

1-butanol

- Causes severe eye irritation and possible eye injury.Breathing vapors may cause

drowsiness and dizziness. Causes skin and respiratory tract irritation. May be

harmful if swallowed. Aspiration hazard if swallowed. Can enter lungs and cause

damage. May cause central nervous system depression.

- Wear chemical splash goggles, protective gloves, and clothing to prevent exposure.

Carbon tetrachloride

- May be fatal if inhaled, absorbed through the skin or swallowed. Causes eye, skin,

and respiratory tract irritation. Aspiration hazard if swallowed. Can enter lungs and

cause damage. Cancer suspect agent. May cause liver and kidney damage. May

cause central nervous system effects. This is a CFC substance which destroys

ozone in the upper atmosphere. Destruction of the ozone layer can lead to

increased ultraviolet radiation which, with excess exposure to sunlight, can lead to

an increase in skin cancer and eye cataracts. Marine pollutant.

- Wear chemical safety goggles, protective gloves, and clothing to prevent exposure.

Bromine


37

- Strong oxidizer. Contact with other material may cause a fire. Corrosive. Causes

eye and skin burns. May cause severe respiratory tract irritation with possible

burns. May cause severe digestive tract irritation with possible burns. Lachrymator

(substance which increases the flow of tears). May cause central nervous system

effects. May cause cardiac disturbances. May cause liver and kidney damage.

- Wear chemical goggles and face shield, protective gloves, and clothing to prevent

exposure.

Calcium carbide

- Dust may irritate respiration system, serious burns may occur because chemical

reacts quickly with water to form acetylene & calcium hydroxide in vigorously

exothermic reaction. Acetylene may displacing oxygen.

- Wear chemical safety goggles, protective gloves, and clothing to prevent skin

exposure.


Give the products these following reactions:


38Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

39

VII. REPORT FORMAT

Name ______________ Date

______________

Partner______________ Lab. Assistant

______________

REPORT SHEET

Solubility of Hydrocarbon

Sample

Solubility

Water 1-butanol Ligroin

heptane1-octenetoluene

Flammability of Hydrocarbon

S Flammability


40

ample

Type ColorCarbon

Total Residue


Effect of Bromine in Carbon Tetrachloride

Sample

Change of Color

10-20 drops

Iron Tack

Heating

Blue Litmus Paper

heptane1-oc


41

tenetoluene


42

Name ______________ Date

______________


______________

REPORT SHEET

Reaction with Potassium Permanganate

Sample

Reaction

3 dropsAfter shake

Time


Grouping The Substance

Sam

GroupingSaturated Unsaturate

d Aromatic


43

pl123

Preparation and Chemical Properties of Acetylene

SampleChange

carbon tetrachloride

Water Shake

carbon tetrachloride - -potassium

permanganate-


44

Experiment 7IDENTIFICATION OF ALCOHOL

I. OBJECTIVES

To identify several properties of alcohol.

II. INTRODUCTION

Alcohol can be said as organic solvent which is analog to water. In alcohol, hydroxyl

group (-OH) is attached to saturated carbon not at the hydrogen atom as in water. The

hydroxyl group makes physical and chemical properties very different with hydrocarbon.

Structure from hydroxyl group which is strongly affected character of alcohol is a polar bond

between hydrogen-oxygen and a pair of electrons from the oxygen.

Some chemical differences from alcohol depends on the alkyl group structure. One

important thing is how many carbon atom which is bonded with the –C-OH group. Primer,

secondary, and tertiary alcohol have 1,2, and 3 carbon group consecutively, which is attached

at the carbon atom bonded to oxygen atom.

Hydroxyl group from alcohol can make hydrogen bond with water. That is why,

alcohol is soluble in water than in hydrocarbon. All alcohol with low molecular weight is

completely soluble in water, and the solubility of high molecular weight is more likely to

alkane’s solubility. As the size of alkyl group increase, the polar hydroxyl group will give

less contribution to physical properties.

Proton from water molecule is more acidic than proton from hydroxyl group. That is

why proton from hydroxyl group can only be neutralized by strong alkaline.

Proton from hydroxyl group from water can be reduces by active metal and produces

hydrogen gas. This reaction is between active metal and water.


45

Rate of this reaction depends on the alcohol acidity. The most acidic component will

be the most reactive agent to sodium.

Hydroxyl group from alcohol can be replaced by other groups such as halogen. The

rate of reaction depends on the structure of alkyl group. The replacement of hydroxyl group

from chlorine group can be done with some reagent. One of the example is Lucas reagent

which consists of ZnCl2 and HCl.

For tertiary alcohol, the reaction is very fast in room temperature. Secondary alcohol

reacts in 5-10 minutes. Primary alcohol can react after hours in room temperature. Because

alkyl chloride is not soluble in Lucas reagent, then the turbidity means that the reaction has

occurred. Time needed to start the reaction indicates the type of structure in alcohol.

Primary, secondary, and tertiary alcohols give different reaction to oxidizing agents.

Type of oxidizing agent which is typically used is sodium dichromate (Na2Cr2O7) in dilute

sulphate acid solution.

Chromium is reduced to Cr3+ in the reaction. Dichromate solution is yellowish orange,

while Cr3+ is green. Therefore, the alcohol oxidation by potassium dichromate is indicated by

the change of colour from chromium species.

The structure of alcohol below reacts continuously with iodine and NaOH to produce

iodoform, yellow solid.

This reaction can be used to characterize the structure of alcohol.


46


III.1. Equipment

1. Test tube 10x75 mm

2. Test tube 16x150 mm

3. Beaker glass

4. Pipettes

5. Test tube rack

III.2. Chemicals

1. Methanol

2. Ethanol

3. 1-propanol

4. 2-propanol

5. 1-butanol

6. 2-butanol

7. 2-methyl-2-propanol

8. 1-pentanol

9. 1-octanol

10. 1% Sodium dicromate solution (Na2Cr2O7 . 2H2O)

11. 1M NaOH solution

12. 6M HCl solution

13. Iodine-Potassium iodide solution

14. Lucas reagent

IV. PROCEDURES

IV.1. The Solubility of Alcohol in Water

1. Put 1 ml of water in small test tube.

2. Add some drops of ethanol while shaking until it does not soluble anymore or until

the volume is twice from initial volume of water.

3. Repeat the test with another alcohol (1-butanol, 2-butanol, 2-methyl-2-propanol, 1-

pentanol, and 1–octanol).


47

4. Characterize each alcohol: soluble, a litte soluble, or totally soluble. Write down on

your report.

IV.2. Reactivity of Alcohol with Sodium

1. Your laboratory assistant will react sodium metal with methanol, ethanol, 1-propanol,

2-propanol, and 2-methyl-2-propanol.

2. Write down your observation in report, write down the chemical equation from these

reactions.

3. Put the level of acidity of alcohol in order from their O-H bonds.

IV.3. Lucas Test

1. Put 1 ml of 1-butanol in 16 x 150 mm test tube, add Lucas reagent.

2. Close the test tube, mix the solution until it is soluble by shaking. Settle down in room

temperature.

3. Observe what happens after 5 minutes and after 30 minutes.

4. Repeat the test with other samples: 2-butanol and 2-methyl-2-propanol.

5. Write down your observation and write down the chemical equation from these

reactions.

6. If there is no reaction, mark with “NR”.

IV.4. Oxidizing Alcohol

1. Put 1 ml of alcohol samples and add 10 drops of HCl 6 M in test tubes.

2. Add 1 drop of 10% Na2Cr2O7 solution and mix them well.

3. Look and observe the change of colour.

IV.5. Iodoform Reaction

1. Add 4 drops of 1-propanol in 1 mL of methanol and 1 mL of water.

2. Add 2 ml of NaOH 3M solution.

3. Add drop by drop the I2-KI solution until yellow solid forms, CHI3 , or until the colour

is brown after the mixing at least 2 minutes.

4. Settle down the test tube for 5 minutes, observe what happens.

5. Repeat the test by changing 1–propanol with 2-propanol, 2-butanol, and 2-methyl-2-

propanol.



48


Methanol

- Toxic by ingestion and inhalation. Can be toxic by skin absorption.Affects central

nervous system, especially optic nerve.Causes dizziness, nausea, muscle

weakness, narcosis, respiratory failure.Prolonged or repeated skin contact may

cause irritation.

- Wear safety glasses, protective clothing and masker to prevent exposure

Ethanol

- Flammable liquid and vapor. Cause severe eye irritation and moderate skin

irritation.

- Wear protective clothing and masker to prevent exposure.

1-propanol

- May cause eye and skin irritation. May be harmful if swallowed. May cause

respiratory tract irritation. May cause central nervous system depression. May

cause dermatitis. Hygroscopic (absorbs moisture from the air).

- Wear chemical goggles , protective clothing and masker to prevent exposure

2-propanol

- May cause central nervous system depression. May form explosive

peroxides.Hygroscopic (absorbs moisture from the air). Causes respiratory tract

irritation. Aspiration hazard if swallowed. Can enter lungs and cause damage. This

material has been reported to be susceptible to autoxidation and therefore should

be classified as peroxidizable. Causes eye irritation. Breathing vapors may cause

drowsiness and dizziness. Prolonged or repeated contact causes defatting of the

skin with irritation, dryness, and cracking.

- Wear chemical goggles , protective clothing and masker to prevent exposure

1-butanol

- Causes severe eye irritation and possible eye injury.Breathing vapors may cause

drowsiness and dizziness. Causes skin and respiratory tract irritation. May be

harmful if swallowed. Aspiration hazard if swallowed. Can enter lungs and cause

damage. May cause central nervous system depression.

- Wear chemical splash goggles, protective gloves, and clothing to prevent

exposure.


49

2-butanol

- Breathing vapors may cause drowsiness and dizziness. Causes eye and respiratory

tract irritation. May form explosive peroxides.


exposure.

1-pentanol

- Hygroscopic (absorbs moisture from the air). May cause eye irritation. May cause

irritation of the digestive tract. May cause central nervous system depression. May

cause burning sensations, coughing, wheezing, laryngitis, shortness of breath and

headache. Harmful if inhaled.

- Wear protective gloves, and clothing to prevent exposure.

1-octanol

- Causes eye and skin irritation.May cause respiratory tract irritation. May cause

central nervous system depression.


exposure.

Sodium dicromate solution (Na2Cr2O7 . 2H2O)

- Potentially fatal if swallowed, harmful on contact with the skin, respiratory tract

burns, skin burns, eye burns, mucous membrane burns, allergic reactions, cancer

hazard (in humans)

- Wear chemical goggles , protective gloves, and clothing to prevent exposure.

NaOH solution

- Mucous membrane irritant. Skin: severe irritation, sensitization, dermatitis &

burns. Eyes: irritation,conjunctivitis& burns. Ingestion: damage to mucous

membranes or tissues.


HCl solution

- Corrosive to skin, eyes, nose mucous membranes, respiratory & gastrointestinal

tract. Inhalation:respiratory tract irritation/infection. Severe & fatal

gastrointestinal burns w/necrosis. Severe burns to eyes & blindness. Changes in

pulmonary function, chronic bronchitis,dermatitis, tooth erosion, & conjunctivitis.

- Wear splash chemical goggles, protective gloves, and clothing to prevent

exposure.


50

Iodine-Potassium iodide solution

- May cause respiratory tract irritation. May cause skin irritation. May cause eye

irritation. May cause digestive tract irritation.

- Wear chemical safety goggles , protective gloves, and clothing to prevent

exposure.


1. 1,2-Hexanediol is very soluble in water, while 1-hexanol is not soluble. Explain the

reasons.

2. A lab researcher has 4 compounds (a, b, c, d) with chemical formula C4H10O. All the

compounds react with sodium and free hydrogen. In Lucas test, compound d reacts

very fast b reacts after heated, while a and c react but very slow. Write down the

structure of b and d! What is the possible structure of a and c?

3. A compound with formula C3H8O does not react with sodium, Lucas reagent, or

sodium dichromate solution. Write down the structure. Explain the character of the

not reactive compound!

4. There are 8 isomeric alcohol with formula C5H12O. Only two of them react with

iodoform test. Write down the structure of the two compounds.

5. Write down the products from the reactions below, if there is no reaction happens,

write “NR”:

a.

b.

c.

d.

e.

f.


51

g.


52

VII. REPORT FORMAT

Name ______________ Date

______________


______________

REPORT SHEET

The Solubility of Alcohol in Water

SampleCharacterize

SolubleLittle

SolubleTotally Soluble

ethanol1-butanol 2-butanol

2-methyl-2-propanol

1-pentanol1–octanol

Reactivity of Alcohol with Sodium

Sample

ReactivityChange

Chemical Equation

Level of Acidity OH-Bond

methanolethanol

1-propanol 2-propanol2-methyl-2-

propanol

Lucas Test

Sample Lucas Test5 m

10 min

Chemical Equation


53

inute

ute

1-butanol2- butanol

2-methyl-2-propanol


54

Name ______________ Date

______________


______________

REPORT SHEET

Oxidizing Alcohol

Iodoform Reaction


SampleColor Change

1 drop Shakemethanolethanol

1-propanol2- propanol1-butanol2-butanol

2-methyl-2-propanol

1-pentanol1–octanol

55

SampleAmount

I2-KI

Color Change

2 minutes5

minutesmethanol

1-propanol2- propanol2-butanol

2-methyl-2-propanol


56

Experiment 8LIPID, OIL, SOAP, AND DETERGENT

I. OBJECTIVES

1. To understand several properties of oil and lipid

2. To understand the soap-making procedures

3. To know the existence of phosphate in commercial detergent

II. INTRODUCTION

Triglyceride, one kind of lipid, is ester from alcohol glycerol and long chain

carboxylic acid.

Triglyceride consists of acid with 8 to 12 carbon atom and mix of different types of

acid. If most of the acid is not saturated, then glycerides will be liquid and classified as oil.

Glycerides which have more saturated acid will have higher melting point and classified as

lipid/fat.

Hydrolysis of lipid or oil with base will produce glycerol and salt from the acid, it is

known as saponification. Soap is salts from long chained carboxylic acid. Sodium and

potassium salts are water soluble, while salts from magnesium, calcium, and iron are not

water soluble.

Detergent is salts from aryl sulfonates or alkyl sulfates.


57

Since calcium salts from aryl sulfonate and alkyl sulfate are water soluble, detergent

is usually used in hard water, while soap will produce not soluble precipitate.

Every year, Americans use millions kilogram of detergent to wash clothes or other

things. Nearly every gram from detergent flows to lake or river. Most of laundry products

contain phosphate which will make algae fertile in the water. Phosphate act as fertilizer to

algae in the same form as phosphate when it make plants or grass fertile in garden. Algae

consume dissolved oxygen in water in a large number. Concentration of dissolved oxygen

will reduce so it be difficult for the life of fishes or other sea animal, hence, it will disturb

ecosystem equilibrium.

In this experiment, commercial detergent will be tested to know the existence of

phosphate in it. The basic of this reaction is chemical reaction between phosphate anion and

molybdate anion in acid solution.

Ammonium molybdate solution, (NH4)6Mo7O24, is added to former acidic solution. If

the sample contains phosphate anion, precipitate of ammonium phosphomolybdate

(NH4)3PMo12O40will be well separate and light yellow solid will form.

In this experiment, practitioners will be asked to bring a few sample of liquid or

powder detergent. Make sure to check the label to determine whether the product contain

phosphate. The sample will be tested with other practitioners’ samples to know whether there

is phosphate or not.


III.1. Equipment

1. 16 x 150 mm test tube

2. 10 x 75 mm test tube

3. Reflux instrument

4. Pipettes

5. Glass stirring rod

6. Beaker glass

III.2. Chemicals

1. Cotton seed oil


58

2. Hexane

3. Carbontetrachloride

4. 5% Bromine in carbontetrachloride solution

5. Ethanol 95%

6. NaOH solution

7. High concentration of HCl solution

8. A piece of soap

9. Calcium chloride 0.1 M

10. Magnesium chloride 0.1 M

11. Iron (III) chloride 0.1 M

12. Ammonium molybdate solution 0.2 M

13. Nitric acid 6M

14. Litmus paper or pH indicator paper

15. Mineral oil

IV. PROCEDURES

IV.1. The Solubility of Cotton Seed Oil

1. Put 0.5 mL (about 10 drops) cotton seed oil in each four 16x150 mm test tubes.

2. Add 1 mL of water to the first tube, 1 mLof ethanol to the second tube, 1 mL of

hexane to the third tube and 1 mL carbon tetrachloride to the fourth tube.

3. Shake the test tubes, write down the solubility of each solution in the test tube.

4. Add 5 mL of additional solvent.

5. Shake each tube strongly, observe if the oil is soluble now.


IV.2. Unsaturated Triglyceride

1. Use 2 mL of the solution between carbon tetrachloride and cotton seed oil which has

been done in experiment A for this experiment.

2. Add drop by drop 5% Bromine in carbon tetrachloride solution.

3. Calculate the amount of drops needed to produce bromine color effect of the solution.

4. Put 0.1 g of Crisco into 1 mL of carbon tetrachloride.

5. Repeat step 2 and 3.



59

IV.3. Soap

Attention: Sodium hydroxide is caustic compound, do not touch this compound. Wash your

hands as soon as you feel soapy. Sodium hydroxide can cause eye irritation and

blindness. Clean up the contaminated equipment.

IV.3.1. Preparation

1. Fuse 5 g of sodium hydroxide into 10 mL of distillate water and into 25 mL ethanol in

125 mL Erlenmeyer flask, put 5 g of triglyceride into the reflux flask.

2. Add some boiling chips into the flask.

3. Prepare the reflux instrument as it is shown in Picture 14. Ask your assistant to check

your tool.

4. Reflux the flask content for about 30 minutes or until the solution becomes pure and

homogen.

5. Move the soapy solution from heat, cool the flask and add about 80 mL of high

concentrated sodium chloride solution.

6. Shake the solution comprehensively and collect precipitated soap with the absorb

filtration.

IV.3.2. Equipment

1. Prepare 1 g of soap solution (from the previous result of reflux) in 50 mL boiling

distillate water.

2. Prepare the same solution with commercial soap and detergent.

IV.3.3. Alkaline Characteristic

1. Test the pH from each solution with Litmus paper.


IV.3.4. Emulsion Characteristic

1. Place 3 drops mineral oil to each four test tubes.

2. Put in 5 mL of distillation water to the first tube, 5 mL soap solution (experiment

result) to the second tube, 5 mL commercial soap to the third tube and 5 mL detergent

solution to the fourth tube.

3. Shake each tube for a minute.


IV.3.5. The Effect of Metal Salt

1. Put 5 mL of your soap solution experiment to each three test tubes.


60

2. Add2 mLof Calcium chloride 0.1 M to the first tube, Magnesium chloride 0.1 M to

the second tube and Iron (III) chloride 0.1 M to the third tube.


4. Repeat this experiment with commercial soap and detergent solution.

IV.4. Phosphate Qualitative Test in Detergent

1. Phosphate test is very sensitive. Therefore, wash your test tube until clean or you

better use other new test tube.

2. Add about 60 mg phosphate (like a grain of hulled rice) to the test tube.

3. Add 8 drops of HNO3 6 M. Detergent that contains carbonate will cause foaming

when HNO3 is added. If this happens, keep up adding drop by drop of HNO3 until the

foam is not formed. Then, add again 8 drops of HNO3.

4. If the detergent is in liquid form then use about 15-20 drops in this experiment.

5. Using the magnetic stirrer, mix the solution smoothly.

6. Add 2 drops of ammonium molybdate solution 0.2 M and heat the tube in hot water

for about 5 minutes.

7. If it contains phosphate, yellow precipitate will appear.


Cotton seed oil

- May cause irritation. This is expected to be a low hazard for usual industrial

handling.

- Wear appropriate protective eyeglasses, protective gloves, and protective clothing

to prevent skin exposure.

Hexane

- Extremely flammable liquid and vapor. Vapor may cause flash fire. Possible risk

of impaired fertility. Breathing vapors may cause drowsiness and dizziness.

Dangerous for the environment. May cause nervous system effects.

- Wear appropriate protective eyeglasses, protective gloves, and protective clothing

to prevent skin exposure

Carbontetrachloride

- May be fatal if inhaled, absorbed through the skin or swallowed. Causes eye, skin,

and respiratory tract irritation. Aspiration hazard if swallowed. Can enter lungs Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

61

and cause damage. Cancer suspect agent. May cause liver and kidney damage.

May cause central nervous system effects. This is a CFC substance which destroys

ozone in the upper atmosphere. Destruction of the ozone layer can lead to

increased ultraviolet radiation which, with excess exposure to sunlight, can lead to

an increase in skin cancer and eye cataracts. Marine pollutant.

- Wear chemical safety goggles, protective gloves, and clothing to prevent

exposure.

Bromine

- Strong oxidizer. Contact with other material may cause a fire. Corrosive. Causes

eye and skin burns. May cause severe respiratory tract irritation with possible

burns. May cause severe digestive tract irritation with possible burns.

Lachrymator (substance which increases the flow of tears). May cause central

nervous system effects. May cause cardiac disturbances. May cause liver and

kidney damage.

- Wear chemical goggles and face shield, protective gloves, and clothing to prevent

exposure.

NaOH





HCl solution






exposure.

Soap

- May cause eye and skin irritation. May cause respiratory and digestive tract

irritation. Good laboratory procedures are recommended when handling this

compound. This is expected to be a low hazard for usual industrial handling.


62

- Wear appropriate protective clothing to prevent skin exposure.

Calcium chloride

- May cause severe eye, skin and respiratory tract irritation with possible burns.

May be harmful if swallowed. May cause cardiac disturbances. Hygroscopic

(absorbs moisture from the air).

- Wear splash chemical goggles, protective gloves, and clothing to to minimize

contact with skin.

Magnesium chloride

- May cause eye irritation.

- Wear splash chemical goggles, protective gloves, and clothing to to minimize

contact with skin.

Iron (III) chloride

- Harmful if swallowed, inhaled or absorbed through skin.


exposure.

Ammonium molybdate

- Causes eye and skin burns. Strong oxidizer. Contact with other material may

cause a fire. Causes severe digestive and respiratory tract burns.

- Wear protective goggles, protective gloves, and clothing to prevent exposure.

Nitric acid

- May be fatal if inhaled. Causes severe eye and skin burns. Causes severe

respiratory and digestive tract burns. Strong oxidizer. Contact with other material

may cause a fire. Acute pulmonary edema or chronic obstructive lung disease may

occur from inhalation of the vapors of nitric acid. Corrosive to metal.

- Wear chemical splash goggles and face shield, butyl rubber gloves, and clothing

to prevent skin exposure

Mineral oil


irritation.

- Wear appropriate protective eyeglasses, protective gloves, protective clothing to

prevent skin exposure.


63


1. From all of the solvents that have been experimented, which is the best solvent to

vanish oil stain or fat from clothes?

2. How many gram of bromine needed to react completely with 1 mol triglyceride that

contains only oleic acid?

3. Why do we use saturated concentration sodium chloride solution to precipitate soap?

4. What reaction will happen when calcium ion is added to the soap solution?

5. Do metal salt solution from the carboxylic acid and sulphate alkyl look the same as the

metal salt solution from CO32- and SO4

2-

6. Arsenate Ion, AsO43- will react with ammonium molybdate, same with phosphate.

Explain why and what ion will be produced?


64

VII. REPORT FORMAT

Name ______________ Date ______________

Partner______________ Lab. Assistant ______________

REPORT SHEET

The Solubility of Cotton Seed Oil

No. SampleSolubility

Shake Add Solvent Shake1 Water2 Ethanol3 Hexane4 Carbon tetrachloride

Unsaturated Triglyceride

No Sample Amount of Drops Need1 Cottonseed Oil2 Crisco

Soap

Alkaline Characteristic

No Sample Colour of Litmus Paper1 Soap2 Commercial soap3 Detergent

Emulsion Characteristic

No Sample Characteristic1 Mineral Oil2 Soap3 Commercial Soap

The Effect of Metal Salt

No. SampleSolution

Calcium chloride Magnesium chloride Iron (III) chloride1 Soap2 Commercial soap3 Detergent


65

Experiment 9EXTRACTION AND IDENTIFICATION OF

FATTY ACIDS FROM CORN OILI. OBJECTIVES

To extract fatty acids from neutral fats.

To convert them to their methyl esters.

To identify them by thin-layer chromatography.

II. INTRODUCTION

Fats are esters of glycerol and fatty acids. Liquid fats are often called oils. Whether a

fat is solid or liquid depends on the nature of the fatty acids. Solid animal fats contain mostly

saturated fatty acids, while vegetable oils contain high amounts of unsaturated fatty acids. To

avoid arteriosclerosis, hardening of the arteries, diets which are low in saturated fatty acids as

well as in cholesterol are recommended.

Note that even solid fats contain some unsaturated fatty acids, and oils contain

saturated fatty acids as well. Besides the degree of unsaturation, the length of the fatty acid

chain also influences whether a fat is solid or liquid. Short chain fatty acids, such as found in

coconut oil, convey liquid consistency in spite of the low unsaturated fatty acid content. Two

of the unsaturated fatty acids, linoleic and linolenic acids, are essential fatty acids because the

body cannot synthesize them from precursors; they must be included in the diet.

The four unsaturated fatty acids most frequently found in vegetable oils are:

All the C=C double bonds in the unsaturated fatty acids are cis double bonds, which interrupt

the regular packing of the aliphatic chains, and thereby convey a liquid consistency at room

temperature. This physical property of the unsaturated fatty acid is carried over to the

physical properties of triglycerides (oils).


66

In order to extract and isolate fatty acids from corn oil, first, the ester linkages must be

broken. This is achieved in the saponification reaction in which a triglyceride is converted to

glycerol and the potassium salt of its fatty acids:

In order to separate the potassium salts of fatty acids from glycerol, the products of

the saponification mixture must be acidified. Subsequently, the fatty acids can be extracted

by petroleum ether. To identify the fatty acids that were isolated, they must be converted to

their respective methyl ester by a perchloric acid catalyzed reaction:

The methyl esters of fatty acids can be separated by thin-layer chromatography

(TLC). They can be identified by comparison of their rate of migration (R f values) to the Rf

values of authentic samples of methyl esters of different fatty acids (Fig. 4.1).

Figure 4.1 TLC Chromatogram

Rf = distance travelled by fatty acid/distance travelled by the solvent front.


67


III.1. Equipment

1. Aluminum foil

2. Polyethylene gloves

3. 15 x 6.5 cm silica gel TLC plate

4. Capillary tubes open on both ends

5. Heat lamp

6. 18.Water bath

7. Ruler

8. Drying oven, 110 OC

III.2. Chemicals

1. Corn oil

2. Methyl palmitate

3. Methyl oleate

4. Methyl linoleate

5. Petroleum ether (b. p. 30–60 OC)

6. 0.5 M KOH in ethanol

7. Concentrated HCl

8. Anhydrous Na2SO4

9. Methanol: perchloric acid mixture (95:5)

10. Hexane: diethyl ether mixture (4:1)

11. Iodine crystals, I2

IV. PROCEDURES

IV.1. Extraction of Fatty Acids

1. Weigh a 50-mL Erlenmeyer flask and record the weight on your Report Sheet (1).

2. Add 2 mL of corn oil and weigh it again. Record the weight on your Report Sheet (2).

3. Add 5 mL of 0.5 M KOH in ethanol to the Erlenmeyer flask. Stopper it. Place the

flask in a water bath at 55 OC for 20 min.

4. When the saponification is completed, add 2.5 mL of the concentrated HCl. Mix it by

swirling the Erlenmeyer flask. Transfer the contents into a 50-mL separatory funnel.

Add 5 mL of petroleum ether. Mix it thoroughly. Drain the lower aqueous layer into a


68

flask and the upper petroleum ether layer into a glass-stoppered test tube. Repeat the

process by adding back the aqueous layer into the separatory funnel and extracting it

with another portion of 5 mL of petroleum ether. Combine the extracts.

IV.2. Preparation of Methyl Esters

1. Place a plug of glass wool (the size of a pea) into the upper stem of a funnel, fitting it

loosely. Add 10 g of anhydrous Na2SO4. Rinse the salt on to the glass wool with 5 mL

of petroleum ether; discard the wash. Pour the combined petroleum ether extracts into

the funnel and collect the filtrate in an evaporating dish. Add another portion (2 mL)

ofpetroleum ether to the funnel and collect this wash, also in the evaporating dish.

2. Evaporate the petroleum ether under the hood by placing the evaporating dish on a

water bath at 60 OC. (Alternatively, if dry N2 gas is available, the evaporation could be

achieved by bubbling nitrogen through the extract. This also must be done under the

hood.)

3. When dry, add 10 mL of the CH3OH:HClO4mixture (95:5). Place the evaporating dish

in the water bath at 55 OC for 10 min.

IV.3. Identification of Fatty Acids

1. Transfer the methyl esters prepared above into a separatory funnel. Extract twice with

5 mL of petroleum ether. Combine the extracts.

2. Prepare another funnel with anhydrous Na2SO4 on top of the glass wool. Filter the

combined petroleum ether extracts through the salt into a dry, clean evaporating dish.

Evaporate the petroleum ether on the water bath at 60 OC, as before. When dry, add

0.2 mL of petroleum ether and transfer the solution to a clean and dry test tube.

3. Take a 15x6.5 cm TLC plate. Make sure you do not touch the TLC plate with your

fingers. Preferably use plastic gloves, or handle the plate by holding it only at the

edges. This precaution must be observed throughout the whole operation because your

fingers may contaminate the sample. With a pencil, lightly draw a line parallel to the

6.5 edge about 1 cm from the edge. Mark the positions of the five spots, equally

spaced, where you will spot your samples (Fig. 4.2).

[Caution : Strong acid; use gloves with concentrated HCl.]

4. For spots no. 1 and no. 5, use your isolated methyl esters obtained from corn oil. For

spot no. 2, use methyl oleate; for spot no. 3, methyl linoleate; and for spot no. 4,

methyl palmitate. For each sample use a separate capillary tube. In spotting, apply

each sample in the capillary to the plate until it spreads to a spot of 1 mm diameter.


69

Dry the spots with a heat lamp. Pour about 15 mL of solvent (hexane:diethyl ether;

4:1) into a 500 mL beaker. Place the spotted TLC plate diagonally for ascending

chromatography. Make certain that the spots applied are abovethe surface of the

eluting solvent. Cover the beaker lightly with aluminum foil to avoid excessive

solvent evaporation.

Figure 1. Spotting

5. When the solvent front has risen to about 1–2 cm from the top edge, remove the plate

from the beaker. Mark the advance of the solvent front with a pencil. Dry the plate

with a heat lamp under the hood. Place the dried plate in a beaker containing a few

iodine crystals. Cover the beaker tightly with aluminum foil. Place the beaker in a 110 OC oven for 3–4 min. Remove the beaker and let it cool to room temperature. This

part is essential to avoid inhaling iodine vapors. Remove the TLC plate from the

beaker and mark the spots with a pencil.

6. Record the distance the solvent front advanced on your Report Sheet (4). Record on

your Report Sheet (5–9) the distance of each iodine-stained spot from its origin.

Calculate the Rf values of your samples on Report Sheet (10–14).


Corn oil

- May cause irritation. This is expected to be a low hazard for usual industrial

handling.

- Wear appropriate protective eyeglasses, protective gloves, and clothing to prevent

skin exposure.

Methyl palmitate


70

- May cause eye, skin, and respiratory tract irritation. The toxicological properties

of this material have not been fully investigated.


skin exposure.

Methyl oleate


irritation. The toxicological properties of this material have not been fully

investigated.


skin exposure.

Petroleum ether

- Flammable liquid and vapor. Breathing vapors may cause drowsiness and

dizziness. Harmful if inhaled or swallowed. Cancer hazard. May cause eye, skin,

and respiratory tract irritation. Aspiration hazard if swallowed. Can enter lungs

and cause damage. May cause central nervous system depression.


skin exposure.

KOH

- Corrosive. Water-reactive. Causes severe eye and skin burns. Causes severe

digestive and respiratory tract burns. Harmful if swallowed.

- Wear safety eyeglasses, protective gloves, and clothing to prevent skin exposure.

HCl






exposure.

Na2SO4

- May cause eye, skin, and respiratory tract irritation. Hygroscopic (absorbs

moisture from the air).Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

71

- Wear safety eyeglasses, protective gloves, and clothing to prevent skin exposure.

Methanol




cause irritation.

- Wear safety glasses, protective clothing and masker to prevent exposure.


VI.1. Pre-Lab Question

1. Fatty acids can be extracted by petroleum ether. Salts of fatty acids cannot; they are

water soluble. Explain why.

2. Write the formulas of the reaction, converting linolenic acid to its methyl ester.

3. How can one convert the potassium salt of a fatty acid (i.e., potassium oleate) into a

fatty acid (oleic acid)?

4. Why do you have to cool the iodine chamber (the beaker containing the

chromatogram and iodine vapor) from 110C to room temperature?

VI.1. Post-Lab Question

1. Which of the identifiable fatty acids of your corn oil was a saturated fatty acid?

2. Judging from the iodine spots of samples 2, 3, and 4, which fatty acid reacts most

strongly with iodine? Why?

3. What was the role of the anhydrousNa2SO4 in the preparation of the methyl esters

of fatty acids?

4. Given two saturated fatty acids, one a short chain of 10 carbons and the other a long

chain of 20 carbons, which would move faster on the TLC plate? Explain.

5. Considering the Rf values you obtained for the three methyl esters of the fatty acids

in your experiment, how could you achieve a better separation of the spots?


72

VII. REPORT FORMAT

Name ______________ Date ______________


REPORT SHEET

1. Weight of beaker ______________ g

2. Weight of beaker and oil ______________ g

3. Weight of oil ______________ g

Distances on the chromatogram in cm

4. The solvent front ______________

5. Spot no. 1 a______ b______ c______ d______ e______

6. Spot no. 2 ______________

7. Spot no. 3 ______________

8. Spot no. 4 ______________

9. Spot no. 5 a______ b______ c______ d______ e______

Calculated Rf values

10. For spot no.1 [(5)/(4)] a______ b______ c______ d______ e______

11. For spot no. 2 [(6)/(4)] ______________

12. For spot no. 3 [(7)/(4)] ______________

13. For spot no. 4 [(8)/(4)] ______________

14. For spot no. 5 [(9)/(4)] a______ b______ c______ d______ e______

15. How many fatty acids were present in your corn oil?

16. How many fatty acids could you identify? Name the identifiable fatty acids in the

corn oil.


73

Experiment 10PROPERTIES OF CARBOXYLIC ACIDS

AND ESTERSI. OBJECTIVES

To study the physical and chemical properties of carboxylic acids: solubility, acidity,

aroma.

To prepare a variety of esters and note their odors.

To demonstrate saponification.

II. INTRODUCTION

Carboxylic acids are structurally like aldehydes and ketones in that they contain the

carbonyl group. However, an important difference is that carboxylic acids contain a hydroxyl

group attached to the carbonyl carbon.

The carboxylic acid group

This combination gives the group its most important characteristic; it behaves as an acid.

As a family, carboxylic acids are weak acids that ionize only slightly in water. As

aqueous solutions, typical carboxylic acids ionize to the extent of only one percent or less.

At equilibrium, most of the acid is present as un-ionized molecules. Dissociation constants,

Ka, of carboxylic acids, where R is an alkyl group, are 10-5 or less. Water solubility depends

to a large extent on the size of the R-group. Only a few low-molecular-weight acids (up to

four carbons) are very soluble in water.

Although carboxylic acids are weak, they are capable of reacting with bases stronger

than water. Thus while benzoic acid shows limited water solubility, it reacts with sodium

hydroxide to form the soluble salt sodium benzoate. (Sodium benzoate is a preservative in

soft drinks.) Sodium carbonate, Na2CO3, and sodium bicarbonate, NaHCO3, solutions can

neutralize carboxylic acids also.


74

The combination of a carboxylic acid and an alcohol gives an ester; water is

eliminated. Ester formation is an equilibrium process, catalyzed by an acid catalyst.

The reaction typically gives 60% to 70% of the maximum yield. The reaction is a reversible

process. An ester reacting with water, giving the carboxylic acid and alcohol, is called

hydrolysis; it is acid catalyzed. The base-promoted decomposition of esters yields an alcohol

and a salt of the carboxylic acid; this process is called saponification. Saponification means

“soap making,” and the sodium salt of a fatty acid (e.g., sodium stearate) is a soap.

A distinctive difference between carboxylic acids and esters is in their characteristic

odors. Carboxylic acids are noted for their sour, disagreeable odors. On the other hand, esters

have sweet and pleasant odors often associated with fruits, and fruits smell the way they do

because they contain esters. These compounds are used in the food industry as fragrances and

flavoring agents. For example, the putrid odor of rancid butter is due to the presence of

butyric acid, while the odor of pineapple is due to the presence of the ester, ethyl butyrate.

Only those carboxylic acids of low molecular weight have odor at room temperature. Higher-

molecular-weight carboxylic acids form strong hydrogen bonds, are solid, and have a low

vapor pressure. Thus few molecules reach our noses. Esters, however, do not form hydrogen

bonds among themselves; they are liquid at room temperature, even when the molecular

weight is high. Thus they have high vapor pressure and many molecules can reach our noses,

providing odor.


75


III.1. Equipment

1. pH paper (broad range pH 1–12)

2. Litmus paper

3. Pasteur pipet

4. Hot plate

III.2. Chemicals

1. Concentrated H2SO4

2. Glacial acetic acid

3. Benzoic acid

4. Formic acid

5. Salicylic acid

6. Benzyl alcohol

7. Ethanol (ethyl alcohol)

8. 2-Methyl-1-propanol (isobutyl alcohol)

9. 3-Methyl-1-butanol (isopentyl alcohol)

10. Methanol (methyl alcohol)

11. Methyl salicylate

12. 3 M HCl

13. 6 M HCl

14. 2 M NaOH

15. 6 M NaOH

IV. PROCEDURES

IV.1. Carboxylic Acids and Their Salts

IV.1.1. Characteristics of acetic acid

1. Place into a clean, dry test tube (100 x 13 mm) 2 mL of water and 10 drops of glacial

acetic acid. Note its odor by wafting (moving your hand quickly over the open end of

the test tube) the vapors toward your nose. Of what does it remind you?

2. Take a glass rod and dip it into the solution. Using wide-range indicator paper (pH 1–

12), test the pH of the solution by touching the paper with the wet glass rod.


76

Determine the value of the pH by comparing the color of the paper with the chart on

the dispenser.

3. Now, add 2 mL of 2 M NaOH to the solution. Cork the test tube and sharply tap it

with your finger. Remove the cork and determine the pH of the solution as before; if

not basic, continue to add more base (dropwise) until the solution is basic. Note the

odor and compare to the odor of the solution before the addition of base.

4. By dropwise addition of 3 M HCl, carefully reacidify the solution from step no. 3

(above); test the solution as before with pH paper until the solution tests acid. Does

the original odor return?

IV.1.2. Characteristics of benzoic acid

1. Your instructor will weigh out 0.1 g of benzoic acid for sample size comparison. With

your microspatula, take some sample equivalent to the preweighed sample (an exact

quantity is not important here). Add the solid to a test tube (100 x 13 mm) along with

2 mL of water. Is there any odor? Mix the solution by sharply tapping the test tube

with your finger. How soluble is the benzoic acid?

2. Now add 1 mL of 2 M NaOH to the solution from step no. 1 (above), cork, and mix

by sharply tapping the test tube with your finger. What happens to the solid benzoic

acid? Is there any odor?

3. By dropwise addition of 3 M HCl, carefully reacidify the solution from step no. 2

(above); test as before with pH paper until acidic. As the solution becomes acidic,

what do you observe?

IV.2. Esterification

1. Into five clean, dry test tubes (100 x 13 mm), add 10 drops of liquid carboxylic acid

or 0.1 g of solid carboxylic acid and 10 drops of alcohol according to the scheme in

Table 5.1. Note the odor of each reactant.

2. Add 5 drops of concentrated sulfuric acid to each test tube and mix the contents

thoroughly by sharply tapping the test tube with your finger.

[Caution: Sulfuric acid causes severe burns. Flush any spill with lots of water. Use

gloves with thisreagent.]

3. Place the test tubes in a warm water bath at 60OC for 15 min. Remove the test tubes

from the water bath, cool, and add 2 mL of water to each. Note that there is a layer on

top of the water in each test tube. With a Pasteur pipet, take a few drops from this top

layer and place on a watch glass. Note the odor. Match the ester from each test tube


77

with one of the following odors: banana, peach, raspberry, nail polish remover,

wintergreen.

Table 10.1 Acids and Alcohols

Test Tube No. Carbocylic Acid Alcohol

1 Formic Isobutyl

2 Acetic Benzyl

3 Acetic Isopentyl

4 Acetic Ethyl

5 Salicylic Methyl

IV.3. Saponification

This part of the experiment can be done while the esterification reactions are being heated.

1. Place into a test tube (150 x 18 mm) 10 drops of methyl salicylate and 5 mL of 6 M

NaOH. Heat the contents in a boiling water bath for 30 min. Record on the Report

Sheet what has happened to the ester layer (1).

2. Cool the test tube to room temperature by placing it in an ice water bath. Determine

the odor of the solution and record your observation on the Report Sheet (2).

3. Carefully add 6 M HCl to the solution, 1 mL at a time, until the solution is acidic.

After each addition, mix the contents and test the solution with litmus. When the

solution is acidic, what do you observe? What is the name of the compound formed?

Answer these questions on the Report Sheet (3).


H2SO4

- Very hazardous in case of skin contact (corrosive, irritant, permeator), of eye

contact (irritant, corrosive), of ingestion, of inhalation. Liquid or spray mist may

produce tissue damage particularly on mucous membranes of eyes, mouth and

respiratory tract.


exposure.

Glacial acetic acid


78

- Causes severe irritation and burns. May Be harmful if swallowed. Avoid breathing

vapor or dust. Use with adequate ventilation. Avoid contact with eyes, skin, and

clothes. Wash thoroughly after handling. Keep container closed.


exposure.

Benzoic acid

- Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion,

of inhalation. Slightly hazardous in case of skin contact (permeator).


exposure.

Formic acid

- Very hazardous in case of skin contact (irritant), of eye contact (irritant,

corrosive), of ingestion, . Hazardous in case of skin contact (corrosive,

permeator).


exposure.

Salicylic acid

- Hazardous in case of skin contact (irritant), of eye contact (irritant), of ingestion,

of inhalation (lung irritant). Slightly hazardous in case of skin contact (permeator).

Severe over-exposure can result in death.


exposure.

Benzyl alcohol

- Hazardous in case of skin contact (irritant), of eye contact (irritant), of inhalation.

Slightly hazardous in case of skin contact (permeator), of ingestion.


exposure.

Ethanol

- Flammable liquid and vapor. Cause severe eye irritation and moderate skin

irritation.

- Wear protective clothing and masker to prevent exposure.

Methanol (methyl alcohol)


79




cause irritation.

- Wear safety glasses, protective clothing and masker to prevent exposure

HCl





- Wear splash chemical goggles , protective gloves, and clothing to prevent

exposure.

NaOH






VI.1. Pre-Lab Questions

1. Write the structures of the following carboxylic acids:

a) acetic acid

b) formic acid

c) salicylic acid

2. Write the products from the reaction of benzoic acid and sodium hydroxide.

3. Octylformate has the flavor of oranges. Name the alcohol and the carboxylic acid

needed to synthesize this ester.

4. What is a “soap”?

VI.2. Post-Lab Questions

1. How do carboxylic acids and esters differ in their characteristic odors?

2. Write equations for each of the five esterification reactions.


80

3. Benzoic acid and diphenyl ketone are both insoluble in water. Suggest a method for

separating a mixture of these compounds.

VII. REPORT FORMAT

Name ______________ Date ______________


REPORT SHEET

Carboxylic acids and their salts

Characteristics of Acetic AcidProperty Water Solution NaOH Solution HCl Solution

Odor

Solubility

pH

Characteristics of Benzoic AcidProperty Water Solution NaOH Solution HCl Solution

Odor

Solubility

pH

Esterification

Test Tube Acid Odor Alcohol Odor Ester Odor

1

2

3

4

56


81Basic&Organic Chemistry LaboratoryChemical Engineering Department, Faculty of Engineering Universitas Indonesia

82

Name ______________ Date ______________


REPORT SHEET

Saponification

1. What has happened to the ester layer?

2. What has happened to the odor of the ester?

3. What forms on reacidification of the solution? Name the compound.

4. Write the chemical equation for the saponification of methyl salicylate.


83

Experiment 11CARBOHYDRATES

I. OBJECTIVES

To become familiar with the reducing or nonreducing nature of carbohydrates.

To experience the enzyme-catalyzed and acid-catalyzed hydrolysis of acetal groups.

II. INTRODUCTION

Carbohydrates are polyhydroxy aldehydes, ketones, or compounds that yield

polyhydroxy aldehydes or ketones upon hydrolysis. Rice, potatoes, bread, corn, candy, and

fruits are rich in carbohydrates. A carbohydrate can be classified as a monosaccharide

(glucose or fructose); a disaccharide (sucrose or lactose), which consists of two joined

monosaccharides; or a polysaccharide (starch or cellulose), which consists of thousands of

monosaccharide units linked together. Monosaccharides exist mostly as cyclic structures

containing hemiacetal (or hemiketal) groups. These structures in solutions are in equilibrium

with the corresponding open chain structures bearing aldehyde or ketone groups. Glucose,

blood sugar, is an example of a polyhydroxy aldehyde (Fig.11.1).

Figure 11.1 The Structure of D-glucose.

Disaccharides and polysaccharides exist as cyclic structures containing functional

groups such as hydroxyl groups, acetal (or ketal), and hemiacetal (or hemiketal). Most of the

di-, oligo-, or polysaccharides have two distinct ends. The one end which has a hemiacetal (or

hemiketal) on its terminal is called the reducing end, and the one which does not contain a

hemiacetal (or hemiketal) terminal is the nonreducing end. The name “reducing” is given

because hemiacetals (and to a lesser extent hemiketals) can reduce an oxidizing agent such as

Benedict’s reagent.

Fig. 11.2 is an example:


84

Figure 11.2 The structure of maltose a disaccharide.

Not all disaccharides or polysaccharides contain a reducing end. An example is

sucrose, which does not have a hemiacetal (or hemiketal) group on either of its ends (Fig.

11.3).

Figure 11.3 The structure of sucrose.

Polysaccharides, such as amylose or amylopectin, do have a hemiacetal group on one

of their terminal ends, but practically they are nonreducing substances because there is only

one reducing group for every 2,000–10,000 monosaccharidic units. In such a low

concentration, the reducing group does not give a positive test with Benedict’s or Fehling’s

reagent. On the other hand, when a nonreducing disaccharide (sucrose) or a polysaccharide

such as amylose is hydrolyzed the glycosidic linkages (acetal) are broken and reducing ends

are created. Hydrolyzed sucrose (a mixture of D-glucose and D-fructose) will give a positive

test with Benedict’s or Fehling’s reagent as well as hydrolyzed amylose (a mixture of glucose

and glucose containing oligosaccharides). The hydrolysis of sucrose or amylase can be

achieved by using a strong acid such as HCl or with the aid of biological catalysts (enzymes).

Starch can form an intense, brilliant, dark blue-, or violet-colored complex with

iodine. The straight chain component of starch, the amylose, gives a blue color while the

branched component, the amylopectin, yields a purple color. In the presence of iodine, the

amylose forms helixes inside of which the iodine molecules assemble as long polyiodide


85

chains. The helix-forming branches of amylopectin are much shorter than those of amylose.

Therefore, the polyiodide chains are also much shorter in the amylopectin-iodine complex

than in the amylose-iodine complex. The result is a different color (purple). When starch is

hydrolyzed and broken down to small carbohydrate units, the iodine will not give a dark blue

(or purple) color. The iodine test is used in this experiment to indicate the completion of the

hydrolysis.

In this experiment, you will investigate some chemical properties of carbohydrates in

terms of their functional groups.

1. Reducing and nonreducing properties of carbohydrates

a. Aldoses (polyhydroxy aldehydes).All aldoses are reducing sugars because they

contain free aldehyde functional groups. The aldehydes are oxidized by mild

oxidizing agents (e.g., Benedict’s or Fehling’s reagent) to the corresponding

carboxylates. For example,

b. Ketoses (polyhydroxy ketones).All ketoses are reducing sugars because they have

a ketone functional group next to an alcohol functional group. The reactivity of

this specific ketone (also called α-hydroxyketone) is attributed to its ability to

form an α-hydroxyaldehyde in basic media according to the following

equilibrium equations:

c. Hemiacetal functional group (potential aldehydes).Carbohydrates with hemiacetal

functional groups can reduce mild oxidizing agents such as Benedict’s reagent

because hemiacetals can easily form aldehydes through the following equilibrium

equation:


86

Sucrose is, on the other hand, a nonreducing sugar because it does not contain a

hemiacetal functional group. Although starch has a hemiacetal functional group at

one end of its molecule, it is, however, considered as a nonreducing sugar because

the effect of the hemiacetal group in a very large starch molecule becomes

insignificant to give a positive Benedict’s test.

2. Hydrolysis of acetalgroups.Disaccharides and polysaccharides can be converted into

monosaccharides by hydrolysis. The following is an example:


III.1. Equipment

1. Bunsen burner

2. Medicine droppers

3. Microtest tubes or a white spot plate

4. Boiling chips

III.2. Chemicals

1. Fehling’s reagent

2. 3 M NaOH

3. 2% starch solution

4. 2% sucrose

5. 2% fructose

6. 2% glucose

7. 2% lactose

8. 12.3 M H2SO4

9. 0.01 M iodine in KI

IV. PROCEDURES

IV.1. Reducing or Non-reducing Carbohydrates

1. Place approximately 2 mL (approximately 40 drops) of Fehling’s solution (20 drops

each of solution part A and solution part B) into each of five labeled tubes.


87

2. Add 10 drops of each of the following carbohydrates to the corresponding test tubes

as shown in the following table.

Table 6.1 Test Tube Number

Test Tube

no.

Name of

Carbohydrate

1 Glucose

2 Fructose

3 Sucrose

4 Lactose

5 Starch

3. Place the test tubes in a boiling water bath for 5 min. A 600 mL beaker containing

about 200 mL of tap water with a few boiling chips is used as the bath.

4. Record your results on your Report Sheet. Which of those carbohydrates are reducing

carbohydrates?

IV.2 Hydrolysis of Carbohydrates

IV.2.1. Hydrolysis of Sucrose (Acid versus Base Catalysis)

1. Place 3 mL of 2% sucrose solution in each of two labeled test tubes. To the first test

tube (no. 1), add 3 mL of water and 3 drops of dilute sulfuric acid solution (3 M

H2SO4). To the second test tube (no. 2), add 3 mL of water and 3 drops of dilute

sodium hydroxide solution (3 M NaOH).

2. Heat the test tubes in a boiling water bath for about 5 min. Cool both solutions to

room temperature. To the contents of test tube no. 1, add dilute sodium hydroxide

solution (3 M NaOH) (about 10 drops) until red litmus paper turns blue.

3. Test a few drops of each of the two solutions (test tube nos. 1 and 2) with Fehling’s

reagent as described before. Record your results on your Report Sheet.

IV.2.2. Hydrolysis of Starch (Enzyme versus Acid Catalysis)

1. Place 2 mL of 2% starch solution in each of two labeled test tubes. To the first test

tube (no. 1), add 2 mL of your own saliva. (Use a 10 mL graduated cylinder to collect

your saliva.) To the second test tube (no. 2), add 2 mL of dilute sulfuric acid (3 M

H2SO4). Place both test tubes in a water bath that has been previously heated to 45C.

Allow the test tubes with their contents to stand in the warm water bath for 30 min.


88

2. Transfer a few drops of each solution into separate depressions of a spot plate or two

separately labeled microtest tubes. (Use two clean, separate medicine droppers for

transferring.)

3. To each sample (in microtest tubes or on a spot plate), add 2 drops of iodine solution.

Record the color of the solutions on your Report Sheet.

IV.2.3. Acid Catalyzed Hydrolysis of Starch

1. Place 5.0 mL of starch solution in a 15 x 150 mm test tube and add 1.0 mL of dilute

sulfuric acid (3 M H2SO4). Mix it by gently shaking the test tube.

2. Heat the solution in a boiling water bath for about 5 min. Using a clean medicine

dropper, transfer about 3 drops of the starch solution into a spot plate or a microtest

tube and then add 2 drops of iodine solution. Observe the color of the solution. If the

solution gives a positive test with iodine solution (the solution should turn blue),

continue heating.

3. Transfer about 3 drops of the boiling solution at 5-min. intervals for an iodine test.

(Note: Rinse the medicine dropper very thoroughly before each test.) When the

solution no longer gives a blue color with iodine solution, stop heating and record the

time needed for the completion of hydrolysis.


NaOH





Sucrose

Slightly hazardous in case of skin contact (irritant), of eye contact (irritant), of

ingestion, of inhalation.


H2SO4


89

- Very hazardous in case of skin contact (corrosive, irritant, permeator), of eye

contact (irritant, corrosive), of ingestion, of inhalation. Liquid or spray mist may

produce tissue damage particularly on mucous membranes of eyes, mouth and

respiratory tract.


exposure.


VI.1. Pre-Lab Questions

1. Circle and label the hemiacetal functional group and the acetal functional group in the

following carbohydrates:

a. Sucrose

b. Lactose

2. Sucrose is a nonreducing sugar. After complete acid hydrolysis, will there be reducing

groups? How many per sucrose molecule?

3. When a reducing sugar reacts with Fehling’s reagent, what will be the product besides

Cu2O?


90

VI.2. Post-Lab Questions

1. An amylose solution is colorless. The iodine solution is reddish-brown. Yet when you

combine these two solutions, you observe an intense blue color. What changes in

molecular structures give this coloration?

2. The hydrolysis of starch was stopped when the iodine test no longer gave a blue color.

3. Does this mean that the starch solution was completely hydrolyzed to glucose?

Explain.

4. Which hydrolysis of the starch is faster? On the basis of this experiment estimate what

will happen to the digestion of a piece of bread (containing starch) when you chew it

thoroughly?

5. In an unusual disaccharide, two α-D-glucose units are linked together in an

α(11)glycosidic linkage. Is this a reducing or nonreducing disaccharide? Explain.


91

VII. REPORT FORMAT

Name ______________ Date ______________


REPORT SHEET

Reducing or Non-reducing Carbohydrates

Test Tube no.

Name of Carbohydrate

Reducing or Non-reducing Carbohydrates

1 Glucose2 Fructose3 Sucrose4 Lactose5 Starch

Hydrolysis of Carbohydrates

Hydrolysis of sucrose (acid versus base catalysis)Sample Condition of hydrolysis Fehling’s reagent(positive or negative)

1 Acidic (H2SO4)2 Basic (NaOH)

Hydrolysis of sucrose (enzyme versus acid catalysis)Sample Condition of hydrolysis Iodine test (positive or negative)

1 Enzymatic (saliva)2 Acidic (H2SO4)

Acid catalyzed hydrolysis of starchTest Tube Heating Time (min.) Iodine test (positive or negative)

1 52 103 154 20


92

References

Abraham Michael R. and Pavelich J. Michael. 1979. Inquires into Chemistry.

Illinois: Waveland Press Inc.

Bettelheim & Landesberg. Laboratory Experiments for General, Organic, and

Biochemistry. 4th edition. Harcout, Inc.

Daniel et. al. 1970. Experiment Physical Chemistry. 7th ed. McGrawHill.

Franz W. Harper & Maim E. Lloyd. 1968. Essentials of Chemistry in the Laboratory

with Report Forms. 2nd ed. San Fransisco: W.H. Freeman and Co.

Sutrasno et. al. 1991. BukuPetunjukPraktikum Kimia Dasar. JurusanTeknik Gas

danPetrokimia FTUI.


module_basic and organic chem (eng)

Documents

lab work report

lab journal

chemical engineering

chemical engineering

chemical material

chemical properties2

practitioners negligence

white lab jacket