unit 6 - solutions workbook · unit 6 – solutions !3 hilton high school regents / ib chemistry 11...

Hilton High School

Regents / IB Chemistry 11

Unit 6 – Solutions

Name: Set:

Due Date:

Exam Date:

Topic 1: Types of Substances - REVIEW

Topic 2: Solubility of Ionic Compounds

Topic 3: Solution Concentration

Topic 4: Electrolytes – Acids, Bases, & Salts

Topic 5: Properties of Acids & Bases

Topic 6: Neutralization & Titration

Lab: Electrolytes – Acids, Bases, & Salts

Hilton High School Regents / IB Chemistry 11

Essentials – Know, Understand, and Be Able To... Matter is classified as either a pure substance or a mixture of pure substances.

A pure substance (element or compound) has a constant composition and constant properties throughout a given sample, and from sample to sample.

Mixtures are composed of two or more substances that can be separated by physical means (filtration, distillation, chromatography).

When substances are mixed together, either a homogeneous or heterogeneous mixture is formed.

A solution is a homogeneous mixture of a solute dissolved in a solvent.

Some ionic compounds are soluble in water and dissociate into ions.

Other ionic compounds are insoluble in water and form precipitates.

Table F: Determining solubility of ionic compounds in water.

Kinetic Molecular Theory (KMT) describes the relationships of pressure, volume, temperature, velocity, and frequency and force of collisions among gas molecules.

The word concentration describes how much solute has been dissolved in the solvent.

Solution are sometimes described as “dilute” or “concentrated”.

Concentration expressed as Molarity (M), which is the moles of solute dissolved per Liter of solution. Be able to calculate this and be able to calculate how to prepare a solution of given Molarity.

An electrolyte is a substance that dissolves in water and forms a solution capable of conducting an electric current.

In order to carry current, you must have charged particles that can move freely.

Sort compounds as Arrhenius acids, Arrhenius bases, or salts according to their chemical formulae.

Behavior of acids described by the Arrhenius Theory.

The acidity of alkalinity of a solution can be measured by pH.

The relative level of acidity of alkalinity of a solution can be shown by using indicators.

Arrhenius acids yield H3O+ (hydronium ions) as the only positive ions in an aqueous solution.

Arrhenius bases yield OH- (hydroxide ions) as the only negative ions in an aqueous solution.

Given properties, identify substances as Arrhenius acids or Arrhenius bases.

Identify solutions as acid, base, or neutral based upon pH.

Interpret changes in acid-base indicator color.

Neutralization: Arrhenius acid reacts with Arrhenius base to form a salt and water.

Titration: Laboratory technique in which the volume of a solution of known concentration is used to determine the concentration of another solution.

Write simple neutralization reactions when given the reactants.

Calculate the concentration or volume of a solution, using titration data and Table T.

Unit 6 – Solutions ! 1


Topic 1 - Types of Substances – REVIEW

1. Fill in the blanks:

• A mixture is a _______________ (physical or chemical) combination of two or more pure substances.

• _____________________ (heterogeneous or homogeneous) mixtures have uniform composition (i.e. salt water).

• _____________________ (heterogeneous or homogeneous) mixtures are not uniform in composition (bucket of dirt).

2. The Matter Flow Chart:

• Complete this flow chart by placing these terms correctly

• compounds, heterogeneous, homogeneous, elements

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3. Particle Diagrams:

a) Identify each picture as a pure substance, or a mixture.

b) Identify each of the ones you classified as a substance as either an element or a compound. Identify each of the ones you classified as a mixture as either heterogeneous or homogenous.

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Matter

Pure SubstancesMixtures of Substances

Assignment: Matter Review

1. Fill in the blanks: • A mixture is a ________________ (physical or chemical) combination of two or more pure substances.

• ______________________ (heterogeneous or homogeneous) mixtures have uniform composition (ie salt water)

• ______________________ (hetero- or homogeneous) mixtures are not uniform in composition (bucket of dirt)

2. The Matter Flow Chart:

a) Complete this Flow Chart by placing these terms correctly:

compounds heterogeneous homogeneous elements

b) Then place “solutions” under the appropriate category (write under one of the

four lines below)

MATTER

Pure MIXTURES

SUBSTANCES of Substances

__________ _____________

______________ _______________

3. Particle Diagrams: a) Identify each picture as a pure substance or a mixture, then..

b) Identify each substance as either an element or compound, and each mixture as heterogeneous or

homogeneous.



Matter Review

1. Matter is classified as either a pure substance or a mixture of pure substances.a) What are two examples of pure substances

• __________________• __________________

2. A pure substance (element or compound) has a constant composition and constant properties throughout a given sample, and from sample to sample.a) What does it mean to have a ‘fixed ratio’ of elements? _____________________________________

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

3. Mixtures are composed of two or more substances that can be separated by physical means.a) What are three physical methods that can be used to separate substances?

i) _______________________ii) _______________________iii) _______________________

4. When substances are mixed together, either a homogeneous or heterogeneous mixture is formed.a) What is the difference between a homogeneous and a heterogeneous mixture? ______________

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

5. A solution is a homogeneous mixture of solute dissolved in a solvent.a) What makes it a homogenous mixture and not a heterogeneous mixture? ____________________

__________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________



Guided ReadingA solution is a homogenous mixture where one

substance (the solute) is completely and evenly

dispersed in another solvent (the solvent).

Making a solution is a physical change - if salt is

dissolved, it is still salt and the water is still water.

A phase is any part of a system with uniform

composition and properties. In a homogenous

mixture such as a solution, there is only one

phase, meaning the components can not be

visually distinguished. A heterogeneous mixture

consists of more than one phase, meaning the

various components can be visually

distinguished. Solutions are homogenous

mixtures in which the solute will not settle out of

solution over time. In solution the solute exists as

atoms, ions, or small molecules. Solutions can

exist as solids (alloys), liquids, or gases. An alloy

is a combination of two metals.

Question:

1. When a substance is dissolved, is it a physical or a chemical change? ___________ ________________________________________

2. Describe how an alloy is a solution and give an example. (You’ll have to look this up.) ________________________________________ ________________________________________________________________________________________________________________________

• A __________________________ is a physical combination of two or more pure substances.

• ____________________________ mixtures have a uniform composition (i.e. salt water).

• ____________________________ mixtures are not uniform in composition (a bucket of dirt)

• ____________________________ is the material which is dissolved.

• ____________________________ is the material which ‘does the dissolving’.

• ____________________________ is the homogenous mixture formed from a solute in a solvent.

• ____________________________ is any part of a system with a uniform composition.


Word Bank: heterogeneous mixture solution phase homogenous solute solvent


Topic 2 - Solubility of Ionic Compounds

Activity: Dissolving Salts Simulation 1. Define salt:

_____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

2. Go to the following website http://phet.colorado.edu/en/simulation/soluble-salts

3. Click “run now”.

4. Use your mouse to move the shaker up and down four times to put some table salt particles into the water.

a) What is the chemical formula of table salt?

b) Is table salt an ionic or covalent compound? How do you know?

c) What happens to the solid salt lattice when it hits the water?

d) Based on atomic size (radius), which ions are represented by the red dots? The green dots?

e) Describe the motion of the ions in the water.

f) This is now a solution of salt. Write the chemical formula with the appropriate phase labeled.

5. Now move the shaker up and down many more times to add a lot more salt to the water. What starts to happen?

6. When you’ve added enough salt to have a big solid mass of it inside your water, watch what is happening.

a) Are some ions in the solid lattice breaking free into the water? ___________

b) Are some ions in the water becoming attached to the solid lattice? ______________

c) This solution is now in equilibrium. Define equilibrium:


http://phet.colorado.edu/en/simulation/soluble-salts


d) Is this equilibrium a physical or chemical equilibrium? Explain how you decided.

e) Look in the upper right hand corner of the screen at the number of ions “bound” vs. “dissolved.” What do you notice about these numbers now?

f) Explain the equilibrium in the solution in terms of the number of particles bound vs. dissolved.

7. Now use the bottom faucet to drain all the liquid, leaving only the solid lattice. Then use the top faucet to add enough water to cover the solid.

a) What happens to the solid?

b) Why did the solid salt dissolve in the new water, but it wouldn’t dissolve before?

c) Define the term saturated:

8. List 3 ways we could speed up the dissolving of salt in water.

i) ________________________

ii) ________________________

iii) ________________________

9. Now click on the tab at the top that says “slightly soluble salts” and choose “Thallium Sulfide” from the drop- down menu on the top right. Shake thallium sulfate into the water and observe.

a) Describe how thallium sulfate is behaving differently than table salt did.

b) What do you think it means to be a slightly soluble salt?

c) Look at the numbers of “dissolved” vs. “bound” ions in the boxes at the top right. What do you notice? Is this solution at equilibrium? Explain how you decided.



Dissociation Dissociate is a shortened form of ‘dis-associate’. If an ionic compound dissolves in water, it is because the attraction of water molecules for the ions is able to pull the ions apart from each other, overcoming their ionic bonds and causing them to ‘dis-associate’ from each other. Dissociation is a PHYSICAL change because it is easily reversed by evaporating the water.

Draw pictures showing how water molecules will orient themselves when surrounding these ions. The Hydrogen ends of water molecules are + charged and the Oxygen end is – charged. It is useful to draw water like this:

"

Complete the ‘dissociation’ equations below by putting correct coefficients on each blank. Use the example given below to help you. (Study it carefully!!) The bottom half of Table I will be helpful as well. In #4 be sure to include the CHARGES of the ions.

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Assignment: Dissociation

A Closer Look: How do ionic compounds dissociate in water?

“Dissociate” is a shortened up form of “dis-associate”. If an ionic compound dissolves in water,

it is because the attraction of water molecules for the ions is able to pull the ions apart from each

other, overcoming their ionic bonds and causing them to “dis-associate” from each other.

Dissociation is a PHYSICAL change because it is easily reversed by evaporating the water!

Read p. 451 and knowledge gained from viewing the simulation

Is the action of one or several water molecules needed to pull an ion out of its crystal? Explain.

Draw pictures showing how water molecules will orient themselves when surrounding these ions. The

Hydrogen ends of water molecules are + charged and the Oxygen end is – charged. It is useful to draw

water like this:

Complete the “dissociation” equations below by putting correct numbers on each blank.

Study the HCl example on p. 453 and/or the NaOH and KOH examples on p. 589. The bottom

half of Table I will be helpful as well. Here’s an additional example:

H2O K3(PO4) (s) 3 K+1 (aq) + 1 (PO4)

3- (aq)

H2O

1. ____ NaI (s) ___ Na+1 (aq) + ___ I 1- (aq)

H2O

2. ____ Na2S (s) ___ Na+1 (aq) + ___ S 2- (aq)

H2O

3. ____ CaCl2 (s) ___ Ca+2 (aq) + ___ Cl 1- (aq)

H2O

4. ____ Ca3(PO4)2 (s) ___ Ca __+ (aq) + ___ PO4

__- (aq)

K1+

S2-

Assignment: Dissociation

A Closer Look: How do ionic compounds dissociate in water?

“Dissociate” is a shortened up form of “dis-associate”. If an ionic compound dissolves in water,

it is because the attraction of water molecules for the ions is able to pull the ions apart from each

other, overcoming their ionic bonds and causing them to “dis-associate” from each other.

Dissociation is a PHYSICAL change because it is easily reversed by evaporating the water!

Read p. 451 and knowledge gained from viewing the simulation

Is the action of one or several water molecules needed to pull an ion out of its crystal? Explain.

Draw pictures showing how water molecules will orient themselves when surrounding these ions. The

Hydrogen ends of water molecules are + charged and the Oxygen end is – charged. It is useful to draw

water like this:

Complete the “dissociation” equations below by putting correct numbers on each blank.

Study the HCl example on p. 453 and/or the NaOH and KOH examples on p. 589. The bottom

half of Table I will be helpful as well. Here’s an additional example:

H2O K3(PO4) (s) 3 K+1 (aq) + 1 (PO4)

3- (aq)

H2O

1. ____ NaI (s) ___ Na+1 (aq) + ___ I 1- (aq)

H2O

2. ____ Na2S (s) ___ Na+1 (aq) + ___ S 2- (aq)

H2O

3. ____ CaCl2 (s) ___ Ca+2 (aq) + ___ Cl 1- (aq)

H2O

4. ____ Ca3(PO4)2 (s) ___ Ca __+ (aq) + ___ PO4

__- (aq)

K1+

S2-



Using Table F Before you begin, decide if you need help remembering how to turn names into formulas! (You can also just write the formula and check it before you go on determining solubility.

Part A Directions: a) Write the chemical formulab) Determine if it is soluble or insoluble in

water.

1. Lithium bromide

a) ________________

b) ________________

2. Potassium hydroxide

a) ________________

b) ________________

3. Silver nitrate

a) ________________

b) ________________

4. Silver iodide

a) ________________

b) ________________

5. Sodium acetate

a) _________________

b) _________________

6. Aluminum phosphate

a) _________________

b) _________________

Part B Directions: Write a dissociation equation for each of the SOLUBLE compounds only!!



Do you get it? You should know/understand OR be able to:

1. Some ionic compounds are soluble in water and others are not.• How can you determine which compounds dissolve in water and which do not?

2. Ionic compounds that do not dissolve in are said to be insoluble.• Does this mean that the attraction between ions is great or is the attraction of ions for water

greater?

3. Use Table F in order to determine if an ionic compound is soluble or insoluble in water.• Write the formula AND name one compound that does NOT dissolve in water.

• Write the formula AND name one compound that DOES dissolve in water.

4. Draw particle diagrams of a positive ion in solution and a negative ion in solution, with water molecules correctly oriented around it.

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Assignment: Do You Get It?

You Should Know/Understand OR Be Able To:

1. Some ionic compounds are soluble in water and others are not.

How can you determine which compounds dissolve in water and which do not?

2. Ionic compounds that do not dissolve are said to be insoluble.

Does this mean that the attraction between ions is greater or is the attraction of ions for water

greater?

3. Use Table F in order to determine in an ionic compound is soluble or insoluble in water.

Write the fomula AND name one compound that does NOT dissolve in water.

Write the formula AND name one compound that DOES dissolve in water.

4. Draw particle diagrams of a positive ion in solution and a negative ion in solution, with water

molecules correctly oriented around it.

Positive ion Negative ion



Topic 3 - Solution Concentration

Activity: Kool Solutions Purpose: Each group will be assigned a ‘recipe’ for making Kool Aid and will need to calculate how much to make. Then everyone will sample the different solutions to see how the different concentrations taste.

Materials: ALL FOOD SAFE; measuring cups, spoons, plastic or paper cups.

What connection can you make between the taste of the solution and its Molarity?

Observations using all senses

Would you describe the taste

as dilute or concentration?

Copy the Molarity of this Kool Aid solution here

Group 1

Group 2

Group 3

Group 4

Group 5

Group 6


Activity: Kool Solutions

Purpose: Each group will be assigned a “recipe” for making Kool Aid, and

will need to calculate how much to make. Then everyone will sample the

different solutions to see how the different concentrations taste.

Materials: ALL FOOD SAFE measuring cups, spoons, plastic or paper

cups.

Observations using all senses

Would you

describe the taste

as dilute or

concentrated?

Copy the Molarity of

this kool aid solution

here

Group 1

Group 2

Group 3

Group 4

Group 5

Group 6

What connection can you make between the taste of the solution and its Molarity?

_______________________________________________________________________________


Concentration Solutions are made when one substance is SOLUBLE in another and dissolves.

1. Look at the picture below. Which of the two solutions is more concentrated with solute particles? How do you know this? __________________________________________ __________________________________________ __________________________________________ __________________________________________

2. In each pair below, circle the solution which is more concentrated:

a) 10 grams of sugar dissolved in 50 mL of solution, OR

b) 20 grams of sugar dissolved in 50 mL of solution

a) 1.3 moles of NaCl dissolved in 100 mL of solution, OR

b) 1.7 moles of NaCl dissolved in 100 mL of solution.

a) 1.3 moles of NaCl dissolved in 100 mL of solution, OR

b) 1.3 moles of NaCl dissolved in 200 mL of solution

3. Summarize: What does the word ‘concentrated’ mean, in terms of the relative amounts of solute and solvent particles? _____________________________________________________________________ __________________________________________________________________________________________


Important Vocabulary Concentration: A measurement of the amount of a solute that is dissolved in a given amount of a solvent. Concentration can be abbreviated [ ].

Qualitative: Two qualitative ways of describing the concentration of solutions are to use the terms ‘dilute’ and ‘concentrated’.

• Dilute: _________________________________________________________________________

• Concentrated: _________________________________________________________________

Quantitative: An exact way of measuring solution concentration. Usually expressed as MOLARITY.

Assignment: Concentrate! Solutions are made when one substance is SOLUBLE in another and dissolves.

Important VOCABULARY:

Concentration = a measurement of the amount of a solute that is dissolved in a given amount of a

solvent. Concentration can be abbreviated [ ].

Qualitative: Two qualitative ways of describing the concentration of solutions are to use the terms

“dilute” and “concentrated”.

• Dilute = _____________________________________________________________________

• Concentrated = _______________________________________________________________

Quantitative: An exact way of measuring solution concentration. Usually expressed as MOLARITY.

1. Look at the Picture below:

Which of the two solutions is more concentrated with

solute particles? How do you know?

_________________________________________

_________________________________________

_________________________________________

2. In each pair below, circle the solution which is more concentrated:

A) 10 grams of sugar dissolved in 50 mL of solution, OR

20 grams of sugar of dissolved 50 mL of solution

B) 1.3 moles of NaCl dissolved in 100 mL of solution, OR

1.7 moles of NaCl dissolved in 100 mL of solution

C) 1.3 moles of NaCl dissolved in 100 mL of solution, OR

1.3 moles of NaCl dissolved in 200 mL of solution

3. Summarize: What does the word “concentrated” mean, in terms of the relative amounts of

solute and solvent particles? ___________________________________________________


Molarity Ladder Directions: We are building up to a concept in chemistry known as molarity. For this activity, you need to move up the ladder one step at a time. You need to SHOW YOUR WORK.Rung 1: Nomenclature

Rung 2: Formula Mass

Name FormulaIron II phosphate

KCl

Ca(NO3)2

Copper II nitride

LiClO

Manganese VI oxide

Name / Formula Formula Mass (g/mol)Iron II phosphate

KCl

Ca(NO3)2

Copper II nitride

LiClO

Manganese VI oxide



Rung 3: Moles to Grams

Rung 4: Grams to Moles

Name / Formula Answer (g)2.5 moles Iron II phosphate

0.558 moles KCl

0.0034 moles Ca(NO3)2

6.00 moles Copper II nitride

1.0 x 103 moles LiClO

9.5 x 10-3 moles Manganese VI oxide

Name / Formula Answer (moles)23.0 g Iron II phosphate

1.33 g KCl

2.0 g Ca(NO3)2

55.1 g Copper II nitride

1.00 g LiClO

2.3 x 10-6g Manganese VI oxide



Rung 5: Molarity

Rung 6: Molarity (Convert grams to moles first, then divide by the volume)

Name / Formula Molarity (mol/ L)2.5 moles Iron II phosphate in 10.0 L

0.90 moles KCl in .050 L

.0088 moles Ca(NO3)2 in 0.0044 L

2.00 moles Copper II nitride in 4.00 L

0.50 moles LiClO in 2.0 L

25.0 moles Manganese VI oxide in 5.0 L

Name / Formula Molarity (mol/L)23 g Iron II phosphate in 10.0 L

1.33 g KCl in .050 L

2.00 g Ca(NO3)2 in 0.0044 L

55.1 g Copper II nitride in 4.00 L

1.00 g LiClO in 2.0 L

2.3 x 10-6 g Manganese VI oxide in 5.0 L



Rung 7: Molarity (Convert the volume to liters first and then divide the moles by the liters.)

Rung 8: Molarity to grams (Find the number of moles then convert to grams.)

Name / Formula Molarity (mol/L)2.5 moles Iron II phosphate in 85 mL

0.90 moles KCl in 358 cm3

.0088 moles Ca(NO3)2 in 5.0 mL

2.00 moles Copper II nitride in 1000 cm3

0.50 moles LiClO in 0.025 mL

25.0 moles Manganese VI oxide in 2.5 x 104 cm3

Name / Formula Mass of Solute (g)10.0 L of 2.3 M Iron II phosphate

0.050 L of 10.0 M KCl

0.0044 L of 2.50 M Ca(NO3)2

4.00 L of 0.15 M Copper II nitride

2.0 L of 0.080 M LiClO

5.0 L of 5.0 M Manganese VI oxide



Rung 9: Molarity to Volume (Use the equations to find the volume when everything else is known.)

Congratulations!!

You’ve completed the ‘Mol Ladder’.

Be sure to check your work...

Name / Formula Volume of Solution (L)10.0 moles of 2.3 M Iron II phosphate

0.050 moles of 10.0 M KCl

0.0044 moles of 2.50 M Ca(NO3)2

4.00 moles of 0.15 M Copper II nitride

2.0 moles of 0.080 M LiClO

5.0 mols of 5.0 M Manganese VI oxide



Calculating Molarity Use the formula given to you in your chemistry reference tables to answer the following questions.

1. 2.0 moles of sugar are dissolved in 1.0 L of water to make a sugar solution. What is the molarity of the solution?

2. 50 grams of NaCl (table salt) are dissolved in water to make 1 L of solution. What is the molarity of the solution.

3. Concentration of 0.5 moles of NaCl in 2.0 L of water.

4. Number of moles of KBr in 10 L of 0.01 M solution.

5. Number of Liters of 2.5 M NaOH required to give 1.5 moles.

6. What is the molarity when 83 grams of NaOH are dissolved to make 325 mL of solution?

Review: 7. A solution is made of two parts. The substance that is doing the job of dissolving the other

substance is called the ________________. The substance that is being dispersed, or dissolved, is called the ____________________.

8. A solution is made using NaCl and water. In this case, the solute is the _______________ and the solvent is the _____________.

9. Most solutions used by chemists are ‘aqueous’ which means they are solution where _______________ is the solvent.



Do you get it? 1. The word ‘concentration’ describes how much solute has been dissolved in the solvent.

• Does a high concentration indicate a lot or a little solute has been dissolved in solvent?

2. Solutions are sometimes described as ‘dilute’ or concentrated’.• Which of these terms indicates that a lot of H2O has been added?

3. Are solutions homogenous or heterogeneous?

4. One way chemists describe concentration is to express it as molarity (M).• Why does molarity have to be represented by a capital (M) and NOT a lowercase (m)?

5. Calculate solution concentration in molarity (M)• Where can you find the formula to calculate molarity?

• What formula is used to calculate molarity?

6. Describe how to prepare a solution, given the molarity desired.• Using sentences and/or diagrams, explain how you would make 1.5 L of a 2.0 M NaOH solution.

You should tell how many grams of the substance you need to make the solution; not how many moles. You will need to calculate moles first, though.



Topic 4 - Electrolytes - Acids, Bases, & Salts

What is an Electrolyte? For ionic compounds that dissolve in water, describing them as ‘electrolytes’ is appropriate since the crystal will fall apart in water. An electrolyte is a substance that dissolves in water and forms a solution capable of conducting an electric current. The ability of a solution to conduct an electric current depends upon the concentration of ions that are present.

**In other words the MORE IONS there are, the BETTER the solution can conduct electricity!

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Look at the picture above. Which would be the best electrolyte (best conductor)? ____________________ To answer this you first need to write out the formula for each compound.

THINK!! Which of the solutions in the picture is NOT an electrolyte? ___________________

Why? _______________________________________________________________________________________ _____________________________________________________________________________________________

Assignment: What is an Electrolyte?

Here is the picture from p. 488 in your textbook:

For ionic compounds that dissolve in water, describing them as “electrolytes” is appropriate, since the

crystal will fall apart in water. An electrolyte is a substance that dissolves in water and forms a

solution capable of conducting an electric current. The ability of a solution to conduct an electric

current depends upon the concentration of ions that are present.

**In other words the MORE IONS there are, the BETTER the solution can conduct electricity!

Look at the picture above. Which would be the best electrolyte (strongest conductor)?

____________________ To answer this you first need to write out the formula for each compound.

Glucose =

Sodium Chloride =

Calcium Chloride =

In order for a substance to CONDUCT ELECTRICITY (like an electrolyte), 2 conditions MUST exist:

1) There must be CHARGED PARTICLES (ions are an example of a charged particle)

2) The charged particles must be ABLE TO MOVE FREELY (like in a water solution)

THINK!! So, which of the solutions in the picture is NOT an electrolyte? __________________ Why?

Glucose

Sodium chloride

Calcium chloride


In order for a substance to CONDUCT ELECTRICITY (like an electrolyte), 2 conditions MUST exist:

1. There must be CHARGED PARTICLES (ions are an example of a charged particle).

2. The charged particles must be ABLE TO MOVE FREELY (like in a water solution.


1. Electrolytes (whether they are strong or weak) can be divided into three categories. Write a definition based on the types of ions produced for each kind of electrolyte.

Acid:

Base:

Ionic Salt:

2. Categorize each of the following as an acid, base, or ionic salt:1. HBr ___________

2. LiBr ___________

3. LiOH __________

4. Li2SO4 _____________

5. H2SO4 _____________

6. Ca(OH)2 ____________

For the following compounds, check whether it is an electrolyte or a non-electrolyte. If it IS an electrolyte, label it as an ACID, BASE, or IONIC SALT. You may want to refer to Tables K and L for help.

Compound Electrolyte Non-electrolyte

1. NaCl

2. CH3OH (methyl alcohol)

3. C3H5(OH)3 (glycerol)

4. HCl

5. C6H12O6 (sugar)

6. CH3COOH (acetic acid)

7. NaOH

8. C2H5OH (ethyl alcohol)

9. NH4OH (NH3 + H2O)

10. H2SO4



Topic 5 - Properties of Acids & Bases Activity: Acid & Base Simulation 1. Go to the following website http://phet.colorado.edu/en/simulation/acid-base-solutions

2. Click “run now”

3. Copy the equation (along with the white, red, and blue particles) that you see below the beaker.

a) Name the “red” ion and the “blue” ion using Table E on your Reference Tables.

b) Why does this equation have a double arrow?

c) Explain in your own words what you think this equation means.

4. Click the box on the right that says “show solvent”. What is a solvent? What is the solvent in this simulation?

5. Click on the circle labeled “conductivity” on the right. Then use your mouse to lower the black electrode (-) and the red electrode (+) into the liquid. Finally, click on each of the solutions and record your observations:

6. Click on the circle labeled “pH Meter” on the right. Then use your mouse to lower the pH meter into the liquid. Finally, click on each of the solutions and record both the pH reading AND what you see in the magnifying glass.

7. Distinguish between an acid and a base in terms of ion concentration.

8. Distinguish between a strong acid and a weak acid in terms of ion concentration.

9. Distinguish between a strong base and a weak base in terms of ion concentration.

Water Strong Acid Weak Acid Strong Base Weak Base

Water Strong Acid Weak Acid Strong Base Weak BasepH: pH: pH: pH: pH:


http://phet.colorado.edu/en/simulation/acid-base-solutions


Acid, Base, or Salt? The properties of acids and bases are caused by the ions they form in water. Due to the presence of ions, aqueous solutions of both acids and bases are electrolytes. Acids and bases react with each other to form a salt and water. The reaction is a double replacement reaction known as neutralization. (Example: HCl + NaOH → NaCl + H2O) Since acid characteristics are caused by hydronium ions and base characteristics are caused by hydroxide ions, there are some differences as well.

Acids increase the hydronium ion concentration of water. Hydronium ion concentration is measured on the pH scale. Acids have a pH below (less than) 7. They also taste sour, the taste of hydronium. Since acids are polar molecules with metallic hydrogen, they react with active metals to release hydrogen gas. This single replacement reaction is responsible for the fact that acids corrode metals. Acids can be used to clean metals.

Bases on the other hand increase the hydroxide ion concentration of water and reduce the hydronium ion concentration in water. As a result they have a pH above (greater than) 7. Hydroxide ions taste bitter. Bases don’t react with metals, but they are not so kind to skin. Bases feel slippery because they dissolve skin. (Dissolved skin makes a great lubricant.) Substances that dissolve skin are called caustic. Bases can be used to unclog drains or to make soap.

Aqueous solutions of acids and bases look identical. Indicators, substances that react with acids or bases to show a definite color change, are used to distinguish between them. See the table to the right.

Salts are ionic compounds formed during the neutralization reaction between acids and bases. Salts tend not to have the characteristics of either acids or bases because they are generally neutral like water. Salts do dissolve in water, however, to form electrolyte solutions.

Fill in the table below based on the reading and your knowledge of chemistry.

Characteristic Acids Bases

Conductivity

pH

Taste

Indicators

Corrosive / Caustic


Assignment:

Assignment:


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Interpreting pH Solutions that are acidic have pH values less than 7 in value. Alkaline solutions are basic, so they have pH values greater than 7. An acidic solution has more H+1 ions in it than (OH)-1 ions. The opposite is true of basic solutions. “Neutral” solutions contain an equal number of H+1 ions and (OH)-1 ions and have a pH value of 7.

• As pH decreases, the concentration of H+ increases

• As pH changes by one unit, [H+] changes by a factor of 10 (pH is a logarithmic scale)

• A pH of 5 compared to a pH of 6: A pH of 5 is 10 times more acidic.

• A pH of 8 compared to a pH of 5 : A pH of 5 is 1000 times (10x10x10) less acidic.

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Assignment: Important Reading on pH

pH stands for “parts Hydrogen”. (Notice that the H must be capital!)

Solutions that are acidic have pH values less than 7 in value. Alkaline solutions are basic, so they have

pH values greater than 7. An acidic solution has more H+1

ions in it than (OH)-1

ions. The opposite is

true of basic solutions. “Neutral” solutions contain an equal number of H+1

ions and (OH)-1

ions and

have a pH value of 7.




• A pH of 8 compared to a pH of 5: A pH of 5 is 1000 times (10 x 10 x 10) less acidic.

Assignment: pH Practice

1. Given pH in the chart below, fill in the other two columns.

pH Value [H+] in scientific notation [H

+] as a decimal value

1

2

7

9

2. A solution with a pH = 1 is _______ times more concentrated in [H

+] than a solution with a pH = 2.

3. A solution with a pH = 4 is _______ times less concentrated in [H


4. A solution with a pH = 2 is _______ times ______ (more or less) concentrated in [H

+] than a solution

with a pH = 4.

5. Given a solution with a [H+] = 1.0 x 10-6 Molar, what would be the pH of a solution that is 1000 times

more concentrated in [H+]?


Assignment: Important Reading on pH

pH stands for “parts Hydrogen”. (Notice that the H must be capital!)

Solutions that are acidic have pH values less than 7 in value. Alkaline solutions are basic, so they have

pH values greater than 7. An acidic solution has more H+1

ions in it than (OH)-1

ions. The opposite is

true of basic solutions. “Neutral” solutions contain an equal number of H+1

ions and (OH)-1

ions and

have a pH value of 7.




• A pH of 8 compared to a pH of 5: A pH of 5 is 1000 times (10 x 10 x 10) less acidic.


Acids & Bases in Water (IB only)

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Assignment:



More Practice with pH (IB only)

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Assignment: pH Practice

1. Given pH in the chart below, fill in the other two columns.

pH Value [H+] in scientific notation [H

+] as a decimal value

1

2

7

9

2. A solution with a pH = 1 is _______ times more concentrated in [H


3. A solution with a pH = 4 is _______ times less concentrated in [H


4. A solution with a pH = 2 is _______ times ______ (more or less) concentrated in [H

+] than a solution

with a pH = 4.

5. Given a solution with a [H+] = 1.0 x 10-6 Molar, what would be the pH of a solution that is 1000 times

more concentrated in [H+]?



Topic 6 - Neutralization & Titration

Activity: Neutralization

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1. How does the concentration of H+ compare to the concentration of OH─ in solution A?

2. How does the concentration of H+ compare to the concentration of OH─ in solution B?

3. How does the concentration of H+ compare to the concentration of OH─ in solution C?

4. Identify the acidic solution in the model. __________5. Identify the basic solution in the model. __________6. Identify the neutral solution in the model. __________

7. Based upon the information presented in the key of the Model, draw reactants and products that form when an H+ ion is added to an OH– ion.

8. What would happen if solution A and solution B were mixed? Explain your answer.

9. Classify the solution that forms in Exercise 2 (when solution A & B are mixed) as acidic, basic, or neutral. Justify your classification in terms of the concentration of H+ ions and OH─ ions.

10. Can a neutral solution contain H+ and/or OH─ ions? Explain.

Activity: Neutralization

Key Questions:

1. How does the concentration of H+

compare to the concentration of OH─

in solution A?



in solution B?



in solution C?

4. Identify the acidic solution in the model.

5. Identify the basic solution in the model.

6. Identify the neutral solution in the model.

7. Based upon the information presented in the key of the Model, draw reactants and products that form

when an H+

ion is added to an OH─

ion.

8. What would happen if solution A and solution B were mixed? Explain your answer.

9. Classify the solution that forms in Exercise 2 (when solution A & B are mixed) as acidic, basic, or

neutral. Justify your classification in terms of the concentration of H+

ions and OH─

ions.

10. Can a neutral solution contain H+

and/or OH─

ions? Explain.



Neutralization Reactions (Regents)

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Write the products and balance the equation for each of the following reactions.

Example: 2 HBr + 1 Mg(OH)2 → 1MgBr2 + 2 H2O

1. ____ HNO3 + ____ KOH →

2. ____ H2SO4 + ____ NaOH →

3. ____ HCl + ____ LiOH →

4. ____ H2SO4 + ____ KOH →

5. ____ HI + ____ Ca(OH)2 →

Assignment: Neutralization Reactions

When an acid reacts with a base, an ionic salt and water are formed.

HCl + NaOH

H2O +

NaCl

HBr

+

KOH

H2O + KBr

HNO3 + NaOH H2O + NaNO3

H2SO4 + 2 KOH 2 H2O + K2SO4 ( note the equation had to be balanced)

2 HNO3 + Mg(OH)2 2 H2O + Mg(NO3)2 (note the equation had to be balanced)

A neutral solution is formed when the right number of moles of strong acid reacts with strong base.

Neutralization occurs when the concentration of H3O+ ions equals the concentration of OH

- ions.

Directions: Write the products and balance the equation for each of the following reactions.

Example: 2 HBr + 1 Mg(OH)2 1 MgBr2 + 2 H2O

1. ___ HNO3 + ___ KOH

2. ___ H2SO4 + ___ NaOH

3. ___ HCl + ___ LiOH

4. __H2SO4 + ___ KOH

5. ___ HI + ___ Ca(OH)2



Neutralization Reactions (IB only)

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Assignment:



Titration Calculations Use the titration equation on Table T. Show all of your work using the ESA method (Equation, Substitute with units, Answer with units).

1. How much 6.0 M HNO3 is needed to neutralize 39 mL of 2.0 M KOH?

2. How much 3.0 M NaOH is needed to neutralize 30.0 mL of 0.75 M H2SO4?

3. What is the concentration of 20 mL of LiOH if it is neutralized by 60 mL of 4 M HCl?

4. What is the concentration of 60 mL of H3PO4 if it is neutralized by 225 mL of 2 M Ba(OH)2?

5. How much 2 M HBr is needed to neutralize 380 mL of 0.1 M NH4OH?

The answers to the questions above are all integers. Each answer stands for a letter of the alphabet. Write the correct letters in the spaces below to find the solution to the riddle.

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Assignment: Titration Calculations Use the titration equation on Table T. Show all work using the ESA method (Equation, Substitute with

units, Answer with units).



Do you get it? You should be able to know/understand OR be able to:1. In the process of neutralization, an Arrhenius acid reacts with an Arrhenius base.

a) What two products are ALWAYS formed? (this is how I tell if it is a neutralization equation.)

b) Label each compound in the following reaction as an acid, base, salt, or water.

• HCl + NaOH → NaCl + H2O

2. Write simple neutralization reactions when given the reactants.a) Complete the following reaction:

• H2SO4 + NaOH →

3. Calculate the concentration or volume of a solution using titration data and Table T.

a) If 50.0 mL of a 3.0 M HNO3 solution completely neutralized 150.0 mL of KOH, what was the molarity of the KOH solution?



Regents Question Pack - Unit 6 Test Review

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REGENTS QUESTION PACK – Unit 6 TEST REVIEW

Types of Substances: 1. Which physical property makes it possible to separate the components of crude oil by means of distillation?

(1) melting point (2) conductivity (3) solubility (4) boiling point

2. One similarity between all mixtures and compounds is that both:

(1) are heterogeneous (3) combine in a definite ratio

(2) are homogeneous (4) consist of two or more substances

3. When a mixture of water, sand, and salt is filtered, what passes through the filter paper?

(1) water, only (3) water and salt, only

(2) water and sand, only (4) water, sand, and salt

4. Which must be a mixture of substances?

(1) solid (2) liquid (3) gas (4) solution

Solubility: 1. Which of the following compounds is least soluble in water?

(1) copper (II) chloride (3) iron (III) hydroxide

(2) aluminum acetate (4) potassium sulfate

2 Based on Reference Table F, which of these salts is the best electrolyte?

(1) sodium nitrate (3) silver chloride

(2) magnesium carbonate (4) barium sulfate

3. What is the correct IUPAC name for the compound NH4Cl?

(1) nitrogen chloride (3) ammonium chloride

(2) nitrogen chlorate (4) ammonium chlorate

4. Based on Reference Table I, which change occurs when pellets of solid NaOH are added to water and stirred?

(1) The water temperature increases as chemical energy is converted to heat energy.

(2) The water temperature increases as heat energy is stored as chemical energy.

(3) The water temperature decreases as chemical energy is converted to heat energy.

(4) The water temperature decreases as heat energy is stored as chemical energy.

5. What is the correct formula for iron (III) phosphate?

(1) FeP (2) Fe3P2 (3) FePO4 (4) Fe3(PO4)2

6. Given the equation: KNO3(s) + H2O(l) KNO3(aq)

As H2O(l) is added to KNO3(s) to form KNO3(aq), the entropy of the system

(1) decreases (2) increases (3) remains the same

Use this info for #7 & 8:

Given the equation for the dissolving of sodium chloride in water: NaCl(s) + H2O Na+(aq) + Cl

–(aq)

7. Describe what happens to entropy during this dissolving process.

8. Explain, in terms of particles, why NaCl(s) does not conduct electricity.



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Use this info for #9 - 11:

Potassium ions are essential to human health. The movement of dissolved potassium ions, K+(aq), in and out of a

nerve cell allows that cell to transmit an electrical impulse.

9. What is the total number of electrons in a potassium ion?

10. Explain, in terms of atomic structure, why a potassium ion is smaller than a potassium atom.

11. What property of potassium ions allows them to transmit an electrical impulse?

Molarity: 1. How many moles of solute are contained in 200 milliliters of a 1 M solution?

(1) 1 (2) 0.2 (3) 0.8 (4) 200

2. What is the total number of grams of NaI(s) needed to make 1.0 liter of a 0.010 M solution?

(1) 0.015 (2) 0.15 (3) 1.5 (4) 15

3. What is the molarity of a solution of NaOH if 2 liters of the solution contains 4 moles of NaOH?

(1) 0.5 M (2) 2 M (3) 8 M (4) 80 M

4. What is the molarity of a solution containing 20 grams of NaOH in 500 milliliters of solution?

(1) 1 M (2) 2 M (3) 0.04 M (4) 0.5 M

Acids & Bases: 1. Which substance is an Arrhenius acid?

(1) LiF(aq) (2) HBr(aq) (3) Mg(OH)2(aq) (4) CH3CHO

2. When 50. milliliters of an HNO3 solution is exactly neutralized by 150 milliliters of a 0.50 M solution of

KOH, what is the concentration of HNO3?

(1) 1.0 M (2) 1.5 M (3) 3.0 M (4) 0.5 M

3. When the pH of a solution changes from a pH of 5 to a pH of 3, the hydronium ion concentration is

(1) 0.01 of the original content (3) 10 times the original content

(2) 0.1 of the original content (4) 100 times the original content

4. A sample of Ca(OH)2 is considered to be an Arrhenius base because it dissolves in water to yield

(1) Ca2+

ions as the only positive ions in solution

(2) H3O+ ions as the only positive ions in solution

(3) OH– ions as the only negative ions in solution

(4) H– ions as the only negative ions in solution

5. Which reaction occurs when hydrogen ions react with hydroxide ions to form water?

(1) synthesis (2) titration (3) decomposition (4) neutralization



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6. Four flasks each contain 100 milliliters of aqueous solutions of equal concentrations at 25°C and 1 atm.

a. Which solutions contain electrolytes?

b. Which solution has the lowest pH?

c. What causes some aqueous solutions to have a low pH?

d. Which solution is most likely to react with an Arrhenius acid to form a salt and water?

7. Which equation represents a double replacement reaction?

(1) 2 Na + 2 H2O 2 NaOH + H2 (3) LiOH + HCl LiCl + H2O

(2) CaCO3 CaO + CO2 (4) CH4 + 2 O2 CO2 + 2 H2O

8. The only positive ion found in an aqueous solution of sulfuric acid is the

(1) hydroxide ion (2) hydronium ion (3) sulfite ion (4) sulfate ion

9. Which process uses a volume of solution of known concentration to determine the concentration of another

solution?

(1) distillation (2) substitution (3) titration (4) double replacement

10. Which pH change represents a hundredfold increase in the concentration of H3O+1

?

(1) pH 5 to pH 7 (2) pH 13 to pH 14 (3) pH 3 to pH 1 (4) pH 4 to pH 3

11. Which compound is an Arrhenius base?

(1) CH3OH (2) CO2 (3) LiOH (4) NO2

12. Which statement correctly describes a solution with a pH of 9?

(1) It has a higher concentration of H3O+ than OH

– and causes litmus to turn blue.

(2) It has a higher concentration of OH– than H3O

+ and causes litmus to turn blue.

(3) It has a higher concentration of H3O+ than OH

– and causes methyl orange to turn yellow.

(4) It has a higher concentration of OH– than H3O

+ and causes methyl orange to turn red.

13. Which of these 1 M solutions will have the highest pH?

(1) NaOH (2) CH3OH (3) HCl (4) NaCl

14. Which species can conduct an electric current?

(1) NaOH(s) (2) NaCl (s) (3) H2O(l) (4) HCl(aq)

15. A compound whose water solution conducts electricity and turns phenolphthalein pink is

(1) HCl (2) HNO3 (3) NaOH (4) LiCl



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Use this info for #16 – 18:

Indigestion may be caused by excess stomach acid (hydrochloric acid). Some products used to treat indigestion

contain magnesium hydroxide. The magnesium hydroxide neutralizes some of the stomach acid. The amount of

acid that can be neutralized by three different brands of antacids is shown in the data table below.

16. Based on Reference Table F, describe the solubility of magnesium hydroxide in water.

17. Show a correct numerical setup for calculating the milliliters of HCl(aq) neutralized per gram of antacid tablet

for each brand of antacid.

18. Which antacid brand neutralizes the most acid per gram of antacid tablet?

19. Given the following solutions: Solution A: pH of 10

Solution B: pH of 7

Solution C: pH of 5

Which list has the solutions placed in order of increasing H+ concentration?

(1) A, B, C (2) B, A, C (3) C, A, B (4) C, B, A

20. Which of these pH numbers indicates the highest level of acidity?

(1) 5 (2) 8 (3) 10 (4) 12

21. According to the Arrhenius theory, when a base dissolves in water it produces

(1) CO32–

as the only negative ion in solution (3) NH4+1

as the only positive ion in solution

(2) OH-1

as the only negative ion in solution (4) H+1

as the only positive ion in solution

22. Which solution when mixed with a drop of bromthymol blue will cause the indicator to change from blue to

yellow?

(1) 0.1 M HCl (2) 0.1 M NH3 (3) 0.1 M CH3OH (4) 0.1 M NaOH



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Use the following info for questions #23 – 26:

A titration setup was used to determine the unknown molar concentration of a solution of NaOH.

A 1.2 M HCl solution was used as the titration standard. The following data were collected.

23. Calculate the volume of NaOH solution used to neutralize 10.0 mL of the standard HCl solution in trial 3.

Show your work.

24. According to Reference Table M, what indicator would be most appropriate in determining the end point of

this titration? Give one reason for choosing this indicator.

25. Calculate the molarity of the unknown NaOH solution using data from Trial 3. Your answer must include the

correct number of significant figures and correct units.

26. Explain why it is better to use the average data from multiple trials rather than the data from a single trial to

calculate the results of the titration.

Use this info for Questions #27 & 28:

Calcium hydroxide is commonly known as agricultural lime and is used to adjust the soil pH. Before the lime was

added to a field, the soil pH was 5. After the lime was added, the soil underwent a 100-fold decrease in

hydronium ion concentration.

27. What is the new pH of the soil in the field?

28. According to Reference Table F, calcium hydroxide is soluble in water. Identify another hydroxide

compound that contains a Group 2 element and is also soluble in water


unit 6 - solutions workbook · unit 6 – solutions !3 hilton high school regents / ib chemistry 11...

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