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$: CHEMISTRY 30 – UNIT C – CHEMICAL CHANGES OF ... · Web viewCrude oil is heated in the fractionation tower without air being present to reduce the risk of mixtures starting to burn$
CHEMISTRY 30 – UNIT C – CHEMICAL CHANGES OF ORGANIC COMPOUNDS Spring 2017

STUDENT NOTES AND EXAMPLES

Unit C is an introduction to organic chemistry. You will learn about common organic compounds and be able to describe their properties and reactions. You will also explore the significance of organic chemistry in technological applications and how they affect your quality of life. Knowledge and skills acquired in chemistry 20 Diversity and of matter and chemical bonding unit will be essential to success in this unit.

KEY CONCEPTS

Organic compounds Naming of organic compounds Structural formulas Structural isomers Monomers and polymers Aliphatic and aromatic compounds Saturated and un-saturated hydrocarbons Identifying functional groups (alcohols, carboxylic acids, esters, and halogenated hydrocarbons) Organic reactions (addition, substitution, elimination, combustion, polymerization and

esterification)

OUTCOME 1 – Explore organic compounds as a common form of matter

1. ____ define organic compounds as compounds containing carbon, recognizing inorganic exceptions such as carbonates, cyanides, carbides and oxides of carbon.

2. ____ identify and describe significant organic compounds in daily life, demonstrating generalized knowledge of their origins and applications; e.g., methane, methanol, ethane, ethanol, ethanoic acid, propane, benzene, octane, glucose, polyethylene.

3. ____ name and draw structural, condensed structural and line diagrams and formulas, using International Union of Pure and Applied Chemistry (IUPAC) nomenclature guidelines, for saturated and unsaturated aliphatic (including cyclic) and aromatic carbon compounds;

a. containing up to 10 carbon atoms in the parent chain (e.g., pentane; 3-ethyl-2,4-dimethylpentane) or cyclic structure (e.g., cyclopentane)

b. containing only one type of a functional group (with multiple bonds categorized as a functional group; e.g., pent-2-ene), including simple halogenated hydrocarbons (e.g., 2-chloropentane), alcohols (e.g., pentan-2-ol), carboxylic acids (e.g., pentanoic acid) and esters (e.g., methyl pentanoate), and with multiple occurrences of the functional group limited to halogens (e.g., 2-bromo-1-chloropentane) and alcohols (e.g., pentane-2,3-diol)

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4. ____ identify types of compounds from the hydroxyl, carboxyl, ester linkage and halogen functional groups, given the structural formula.

5. ____ define structural isomerism as compounds having the same empirical formulas, but with different structural formulas, and relate the structures to variations in the properties of the isomers.

6. ____ compare, both within a homologous series and among compounds with different functional groups, the boiling points and solubility of examples of aliphatics, aromatics, alcohols and carboxylic acids

7. ____ describe, in general terms, the physical, chemical and technological processes (fractional distillation and solvent extraction) used to separate organic compounds from natural mixtures or solutions; e.g., petroleum refining, bitumen recovery.

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Unit Assessment

Formative

Students must participate in lessons

- complete daily notes and examples.

Concept Checks

Complete daily activities and review new concepts regularly

Quizzes – 2

Labs – 1-2

Summative Unit Exam

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Lesson 1:

1) Define organic compounds as compounds containing carbon, recognizing inorganic exceptions such as carbonates, cyanides and carbides

2) Identify and describe significant organic compounds in daily life, demonstrating generalized knowledge of their origins and applications

STS: Demonstrate an understanding that science and technology are developed to meet societal needs and expand human capability

What is Organic Chemistry?

The early definition related to compounds obtained only from __________________________.

Today, it is a major branch of chemistry that deals with compounds of __________________, called ORGANIC compounds*.

*Carbon compounds that are _____________________ and considered INORGANIC are compounds like:

______________ carbon monoxide (CO(g) ) and carbon dioxide (CO2(g) ), and

Ionic compounds of carbon-based ions, such as carbonate CO32-, cyanide CN-,

and carbide ions, SiC (silicon carbide)

The major source of carbon compounds is still living or previously living things, such as plants, animals and all types of fossil fuels

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Organic or Inorganic??

Why is carbon special?

There are millions or organic compounds and only a thousand inorganic compounds. WHY?

Carbon has a _________________ ___________________ of 4

Remember Lewis Dot Diagrams from Chem 20??

This means carbon can bond extensively and can bond together to form chains effectively = called ________________________

Carbon covalently bonds by sharing 4 pairs of electrons. These bonds may be single, double or triple, all producing stable compounds

Compounds can form with same number of each type of atom but different structures = ___________________________

Determining Lewis Formulas

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Formula Organic or Inorganic?

CaCO3(s)

C25H52(s)

Ca2C(s)

CCl4(l)

CH3COOH(l)

CO2(g)

KCN(s)

C12H22O11(s)


So why do we care about _________________________?

If we know how many bonding e-’s an atom has, we can predict what structure a molecular compound will have

Atom Number of

valence e-

Number of

bonding e-

Bonding

capacity

Lewis Formula

Carbon 4 4 4

Nitrogen

Oxygen

Halogens

Hydrogen

Polymers

Examples of repeating carbon chains:

Isomers

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I.e. Carbon can form 4 single bonds, 2 double bonds, 1 triple and 1 single, or 1 double and 2 singles


Compounds with the same number of each type of atom but different structures (C4H10)

We will talk about this in more detail later

Importance of Organic Chemistry

Building units of all living matter: carbohydrates, proteins, fats

All foods are organic compounds

Photosynthesis is a reaction that makes carbon a part of our food. Carbon is passed along through food chains and sugar from photosynthesis is modified and combined with other materials.

Dead organisms are food for other organisms, or are buried in the earth and converted to fossil fuels like peat, coal and petroleum

Petroleum is the source of fuel and starting material for plastics, fabrics and industrial chemicals

The carbon cycle is an illustration of the interrelationship of all living things with the environment and with technologies that refine and use fossil fuels

We will continually outline the importance of organic compounds in our daily lives

Carbon: The Element of Life VIDEO 20 minutes

Complete the worksheet provided as you watch the following video (20 min)

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Lesson 1 homework

Ensure video worksheet is complete and in your notes to review later

PG 47 Q 1, 4 & 5

Extra Practice – LESSON 1

What is coming up tomorrow?

Naming alkanes, branched alkanes and cycloalkanes

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Lesson 2 : Section 9.2 (pg. 366-374)

1) Name and draw structural, condensed structural, and line diagrams and formulas for saturated and unsaturated aliphatic (including cyclic)

• Containing up to 10 carbon atoms in the parent chain/cyclic structure

• Containing only one type of a functional group or multiple bond

• Using the IUPAC nomenclature guidelines

2) Identify types of compounds from the functional groups, given the structural formula

3) Define structural isomerism and relate to variations in properties

Four Types of Formulas

1. Molecular Formulas C5H10(g)

**Not as useful for organic compounds because so many isomers can exist

2. Structural Formulas

3. Condensed Structural Formulas

4. Line Diagrams

– end of line segment represents carbon

– it is assumed to satisfy each carbon’s octet

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Naming Organic Compounds

__________________________________________ – contains only hydrogen and carbon atoms

Straight line chains of carbon atoms

Alicyclic hydrocarbons have carbon atoms forming a closed ring. Still considered aliphatic - ___________________

Alkanes Alkenes Alkynes

Naming Organic Compounds

In organic chemistry, names have a root and a suffix.

The root describes the number of carbons present in the chain or ring.

The suffix describes the type of compound it is.

Branches are like prefixes, using the root and –yl

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Naming ALKANES

1. Find the parent chain. Use the appropriate root and suffix.

2. Number the carbon atoms, starting from the end closest to the branch(es) so that the numbers are the lowest possible

3. Name branches and their location number on the parent chain (us the suffix –yl for branches)

4. Write the complete IUPAC name, following the format: (number of location, if necessary) – (branch name) (parent chain)

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NOW YOU TRY

If more than one of the same branch exist, use a multiplier to show this (di, tri). Remember to include all numbers

Draw 2,4,6-trimethylheptane

If different branches exist, name them in alphabetical order

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ethyl before methyl (e before m in the alphabet)

If there is more than one branch of the same type, a locating number is given to each branch and a prefix indicating the number of that type of branch is attached to the name.

This numbering prefix does not affect the alphabetical order of the branches

Draw the structural formula for 3,4-dimethylhexane

Summary of Naming Alkanes

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1. Find the parent chain. Use the appropriate root and suffix.

2. Number the parent chain carbon atoms, starting from the end closest to the branch(es) so that the numbers are the lowest possible

3. Identify any branches and their location number on the parent chain (us the suffix –yl for branches)

4. If more than one of the same branch exist, use a multiplier (di, tri) to show this. Remember to include all numbers

5. If different branches exist, name them in alphabetical order

6. Separate numbers from numbers using commas, and numbers from words using dashes (no extra spaces)

Don’t forget

Questions will specifically ask about structural, condensed structural or line structural formulas.

You must be comfortable drawing any of the three

Practice

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Write the IUPAC name for the following

Correct the following names: ** Draw and then re-name

4-ethyl-2-methylpentane

4,5-dimethylhexane

CYCLOALKANES

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Based on evidence, chemists believe that organic carbon compounds sometimes take the form of cyclic hydrocarbons:

Cycloalkane s: Alkanes that form a closed ring

General Formula CnH2n

Two less hydrogens are present than in straight chain alkanes because the two ends of the molecule are joined

Are these considered saturated?? Yes, because they have only single bonds and the max amount of hydrogen's bonded to the carbons

Cyclo-compounds will have a higher boiling point than their straight chain partners (because there is an additional bond present)

Naming CYCLOALKANES

Cycloalkanes are named by placing the prefix cyclo in front of the alkane name, as in cyclopropane and cyclobutane

If branches are present, treat the cycloalkane as the parent chain and identify the branches.

Since there is no end at which to start the numbering, use the lowest numbers possible

Name the following:

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1.

2.

Lesson 2 homework

PG 48 – 49 Q 6- 10



Naming Alkenes, Alkynes, Cycloalkenes and Cycloalkynes

Comparing properties of Isomers

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Naming Organic Compounds: Section 9.3 (pg. 374-380)

Alkenes and Alkynes

Lesson 3:

1) Name and draw structural, condensed structural, and line diagrams and formulas for saturated and unsaturated aliphatic (including cyclic

• Containing up to 10 carbon atoms in the parent chain/cyclic structure

• Containing only one type of a functional group or multiple bond




Structural Isomerism

Compound with the same molecular formula but different structures

They will have different chemical and physical properties – based on their different structures

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Find and name all of the isomers of pentane (C5H12(l))

Alkenes and Alkynes

Alkenes – hydrocarbons containing a double C-C bond

General formula (CnH2n) - (like cycloalkanes)

Alkynes – hydrocarbons containing a triple C-C bond

General formula (CnH2n-2) – (like cycloalkenes)

Alkenes and Alkynes are considered unsaturated compounds. They do not have the maximum number of hydrogen atoms surrounding each carbon.

Reactivity: Alkynes (highest), Alkenes, Alkanes (lowest)

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Naming Alkenes and Alkynes

1. Find the parent chain. It MUST contain the multiple bond.

If the bond is a double, the suffix for the parent chain will be -ene

If the bond is a triple, the suffix for the parent chain will be –yne

2. Count carbon atoms so that the multiple bond will be on the lowest possible number. Indicate the number that the multiple bond falls on directly before the suffix

3. Name branches as before

Draw the following as condensed structural formulas:

4-methylpent-2-yne

methylpropene

(why don’t we need a number?)

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Name the following:

4. It is possible for a molecule to have more than one double bond. These are called alkadienes and have the same general formula as alkynes (CnH2n-2)

If this is the case, indicate both numbers where the double bond is formed, and change the suffix to –diene.

a) Draw buta-1,3-diene:

b) What is the IUPAC name for the following:

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Cycloalkenes and –ynes

The rules for naming cycloalkenes and cycloalkynes are the same as naming cycloalkanes

The numbering for the carbon atoms begins with the double bond; the carbons of the double bond are carbons 1 and 2; lowest numbers possible

Draw 3-methylcyclohexene

as a condensed structural formula

Lesson 3 homework

PG 50-51 Q 1-6

PG 52 Q 1-2



Naming Aromatics

Boiling point and Chemical Properties Analysis

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Naming Organic Compounds:

Aromatics

Lesson 4 : Section 9.4 (pg. 381-385)

1) Name and draw structural, condensed structural, and line diagrams and formulas for aromatic carbon compounds




Aromatics Originally, organic compounds with an aroma or odour were called aromatic compounds

Now, aromatics refer to compounds containing a __________________________________

Benzene’s formula is C6H6, which would suggest a highly unsaturated and reactive compound

Benzene is actually quite ________________ and is considered more stable than alkenes and alkynes

Did You Know?? Benzene is a carcinogen and is found naturally in petroleum – why would this be a problem?

What do we know about benzene?

Formula is C6H6 (3D link)

Unreactive – so no true double or triple bonds

Carbon-carbon bonds are the same length and strength

Each carbon is bonded to a hydrogen

So what does benzene look like??

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http://www.nelson.com/ABchem20-30/teacher/protect/otr/chem2030OTR/attachments/l_animations_simulations/MMDB/dswmedia/database.htm


Common Aromatic Compounds

Include Aspirin and Vanillin (one of the flavour molecules in vanilla)

You will notice many aromatic molecules are often depicted using a condensed structural formula except for the benzene ring, which is shown as a line structural formula.

This combination is commonly used by chemists, and we will use this method when drawing aromatics.

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The three double bonds resonate resulting in an overall bond length somewhere in between a single and a double bond,

explaining benzene’s stability

We will use this line structural

formula to represent

benzene in compounds


Naming Aromatics

1. If an alkyl branch is attached to a benzene ring, the compound is named as an alkylbenzene. Alternatively, the benzene ring may be considered as a branch of a large molecule: in this case, the benzene ring is called a phenyl branch.

2. If more than one alkyl branch is attached to a benzene ring, the branches are numbered using the lowest numbers possible, starting with one of the branches.

Given the choice between two sets of lowest numbers, choose the set that is in both numerical and alphabetical order

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Practice Naming Aromatics Draw 1,2-dimethylbenzene

Are there any isomers of this compound?

There is also classical way of naming these isomers. The arrangements are denoted by the prefixe:s ortho (o), meta (m) and para (p). These names are still used in industry so you may encounter them in other references.

Draw the line structural formula for 1-ethyl-3-methylbenzene, is there another possible name for this compound ?

Draw the line structural formula for 2-phenylpentane

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Draw 3-phenylpent-2-ene

Name the following

Summary

We have now learned about both aliphatic and aromatic hydrocarbons. You will need to be comfortable naming all of the following:

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Lesson 4 homework

PG 53 Q 1-2



Crude Oil Refining and Combustion

Review Aromatic and Aliphatic Compounds

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Properties of Organic Compounds & Crude Oil Refining

Lesson 5: Section 9.5 and 9.6 (pg. 386-400)

1) Compare boiling points and solubility of organic compounds

2) Describe fractional distillation and solvent extraction

3) Describe major reactions for producing energy and economically important compounds from fossil fuels

Physical Properties of Simple Hydrocarbons

Alkanes Non-polar moleculesOnly intermolecular forces are London ForceBoiling point and melting point increase with number of carbonsAll insoluble in water (like dissolves like) – nonpolar and polar don’t mix1-4Cs = gas, 5-16Cs = liquid 17 and up = solid at SATP

Alkenes Non-polar molecules, therefore insoluble in waterBoiling points slightly lower than alkanes with the same number of carbons due to less electrons (unsaturated), resulting in lower London Forces

Alkynes Non-polar molecules, therefore insoluble in waterHigher boiling points than alkanes and alkenes with similar C #sAccepted explanation: Linear structure around triple bond allows electrons to come closer together than in alkanes/enes, resulting in greater London ForceIn reality, triple bond gives these a higher boiling point than alkanes.

Branching The more branching, the less significant the London Force (~lower b.p.) - more surface area in straight chain hydrocarbons allows more separation of charge, resulting in greater London Force - see Table #3 pg. 378 (i.e. pentane (with 5Cs) has a b.p. of 36oC which is much higher than dimethylpropane (5Cs) -12oC) = because branching decreased the strength of the London force

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London Forces – temporary dipoles resulting from an uneven distribution of e- in all molecules

Temporary (-) end will repel e- in neighbouring molecules and so on

Depends on size of molecule (number of e-’s)

Weakest of the intermolecular forces

Dipole-Dipole – only exists in polar molecules

Attraction between + and – ends of molecule

Hydrogen Bonding – super strong force

Only exists when H-N, H-F, H-O bonds are present

Sample Question

Predict the relative order of boiling points of the following compounds (lowest to highest). Explain your reasoning.

Methane Propane Hexane Decane

Lowest -------------------------------------------------------------> Highest

Reasoning:

Which would be soluble in water ?

Crude Oil Refining

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Crude oil is a complex mixture of hundreds of thousands of compounds, all of which have different boiling points

We can take advantage of these different b.p.’s and physically separate the different components using heat

This process is called fractional distillation or fractionation

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A fractional distillation tower contains trays positioned at various levels.

Heated crude oil enters near the bottom of the tower.

The bottom is kept hot, and the temperature gradually decreases toward the top of the tower.

As compounds cool to their boiling point, they condense in the cooler trays. The streams of liquid (called fractions) are withdrawn from the tower at various heights along the tower.

A more detailed look…

The vaporized components of the crude oil rise and gradually cool.

To get from one level to the next, the vapours are forced to bubble through the liquid condensed in each tray.

The figure shows the bubble caps used to allow this to happen.

If a gas cools to its boiling point, it will condense and be piped out through the draining tube

Cracking

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Crude oil is heated in the fractionation tower without air being present to reduce

the risk of mixtures starting to burn or explode


Cracking: large hydrocarbons are broken into smaller fragments

Historically, thermal cracking used extremely high temperatures but created large quantities of solid coke.

Now, catalytic cracking uses a catalyst to speed up the reaction and produce less residual products like tar, asphalt and coke

Example: C17H36(l) C9H20(l) + C8H16(l) + C(s)

larger molecules smaller molecules + carbon

In 1960, hydrocracking was developed, which combines catalytic cracking and hydrogenation and produces no coke.

Example: C17H36(l) + H2(g) C9H20(l) + C8H16(l)

larger molecule + hydrogen smaller molecules

Oil Refining

The refining of crude oil can be divided into two main categories:

1. Physical Processes

Fractional Distillation: see previous slides

Solvent Extraction: solvent is added to selectively dissolve and remove an impurity or to separate a useful product from a mixture

2. Chemical Processes

Cracking – larger molecules are broken down into smaller ones

Reforming – large molecules are formed from smaller ones

These chemical processes are needed because fractional distillation does not produce enough of the hydrocarbons that are in demand (i.e. gasoline) and produces too much of the heavier fractions

Catalytic Reforming and Alkylation

Catalytic Reforming: improves the quality of the gasoline

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aliphatic molecule aromatic molecule + hydrogen

Alkylation: increases the branching; improves the quality of the fuel

aliphatic molecule more branched molecule

(AKA: isomerization because it converts molecules into a branched isomer)

Combustion Reactions

Burning of hydrocarbons in the presence of oxygen

Complete Combustion: abundant supply of oxygen; products are carbon dioxide, water vapour and heat

Ex. C3H8(l) + 5O2(g) 3CO2(g) + 4H2O(g)

Incomplete Combustion: limited supply of oxygen; products are carbon monoxide, soot (pure carbon) or any combination of carbon dioxide, carbon monoxide and soot in addition to water vapour and heat

Ex. 2C8H18(l) + 17O2(g) 16CO(g) + 18H2O(g)

OR 2C8H18(l) + 9O2(g) 16C(s) + 18H2O(g)

** Assume complete combustion unless specified otherwise

Balancing FYI

Ex. 2C8H18(l) + 17O2(g) 16CO(g) + 18H2O(g)

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Can also be balanced using a fraction (you need to be

comfortable using this method) – divide each number by 2

Ex. 2C8H18(l) + 9O2(g) 16C(s) + 18H2O(g)

can also be balanced as …

LESSON 5 homework

Hydrocarbon Review Table (next page)



Concept Check and Quiz 1

Functional Groups and Hydrocarbon Reactions

Halides, alcohols, carboxylic acids, esters and polymers

Addition, Substitution and Elimination, esterfication and polymerization

Hydrocarbon(General Formula)

Description Example(s)

ALKANES

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CYCLOALKANES

ALKENES

CYCLOALKENES

ALKYNES

CYCLOALKYNES

AROMATICS

Organic Chemistry: Part 2

Organic Halides and Alcohols

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Lesson 6: Section 10.2 and 10.3 (pg. 417-435)

1) Name and draw structural, condensed structural and line diagrams and formulas for organic halides and alcohols

2) Identify types of compounds from their functional groups, given the structural formula and name of the functional groups

Organic Halides

Organic compounds where one or more hydrogen has been replaced with halogens (F, Cl, Br, I)

Common example: CFC (chlorofluorocarbons)

Nomenclature is similar to naming branch chains of hydrocarbons, but the branch name used is based on the halogen used

chloro-, fluoro-, bromo-, iodo-

What do you need to know about organic halides?

May by polar or nonpolar molecules or may have a relatively nonpolar (hydrocarbon) end and a polar (halide) end (**Remember Electronegativity differences)

Have higher boiling points than similar hydrocarbons

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Have very low solubility in water but higher solubility than similar hydrocarbons

Are typically good solvents for organic materials such as fats, oils, waxes, gums, resins or rubber

Usually toxic or ecologically damaging (DDTs and PCBs)

Practice Drawing Organic Halides

Draw 1,2-dichloroethane

Draw 2,2,5-tribromo-5-methylhexane

Practice Naming Organic Halides

Name the following:

CH2Cl2

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Alcohols An alcohol is an organic compound that contains the –OH functional group (hydroxyl)

General formula is R-OH (R = rest of molecule)

Alcohols are classified as primary, secondary or tertiary depending on the number of carbons bonded to the carbon that contains the hydroxyl group

Common Alcohols

Methanol (also called wood alcohol) is extremely toxic, causing death and blindness

Ethanol (also known as grain alcohol) is the alcohol found in alcoholic beverages and is used in the production of vinegar

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Gas line antifreeze, windshield de-icer, windshield washer fluid – all contain methanol

Naming Alcohols

1. Locate the longest chain that contains an –OH group attached to one of the carbon atoms. Name the parent alkane

2. Replace the –e at the end of the name of the parent alkane with –ol (i.e. butane becomes butanol)

3. Add a position number before the suffix –ol to indicate the location of the –OH group

REMEMBER to number the main chain of the hydrocarbon so that the hydroxyl group has the lowest possible position numb

4. If there is more than one –OH group (called polyalcohols), leave the –e in the name of the parent alkane and put the appropriate prefix before the suffix –ol (i.e. diol, triol, tetraol)

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5. Name and number any branches on the main chain. Add the names of these branches to the prefix.

Draw 2,3-dimethylbutan-2-ol

Draw line structural formulas for:

1. Cyclohexanol

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2. Phenol

3. The three structural isomers of C5H11OH that are pentanols

What do you need to know about alcohols?

Question: Why is the propane used in a barbecue a gas at room temperature, but propan-2-ol (also known as rubbing alcohol) a liquid at room temperature?

What do you need to know about alcohols?

Question: Glycerol (propane-1,2,3-triol) is more viscous than water, and can lower the freezing point of water. When added to biological samples, it helps to keep the tissues from freezing, thereby

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reducing damage. From your knowledge of the molecular structure of glycerol, suggest reasons to account for these properties of glycerol.

Application Question

Predict the order of increasing boiling points for the following compounds, and give reasons for your answer.

butan-1-ol pentane 1-chlorobutane

Lesson 6 homework

Due tomorrow

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Carboxylic Acids and Esters

Organic Chemistry:

Carboxylic Acids and Esters

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LESSON 7: Section 10.4 (pg. 436-443)

1) Name and draw structural, condensed structural and line diagrams and formulas for carboxylic acids and esters

2) Identify types of compounds from their functional groups, given the structural formula and name of the functional groups

Carboxylic Acids

A carboxyl group is composed of a carbon atom double bonded to an oxygen atom and bonded to a hydroxyl group (-COOH)

Note: Because the carboxyl group involves three of the carbon atom’s four bonds, the carboxyl is always at the end of a carbon chain or branch

Naming Carboxylic Acids

1. Name the parent alkane

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methanoic acid

ethanoic acid

Examples:

Carboxylic acids are weak organic acids


2. Replace the –e at the end of the name of than parent alkane with –oic acid

3. The carbon atoms of the carboxyl group is always given position number 1. Name and number the branches that are attached to the compound.

Draw 3-methylbutanoic acid

Draw trichloroethanoic acid (key ingredient in chemical peels)

CCl3COOH

Draw 3-propyloctanoic acid

Esters

The reaction between a carboxylic acid and an alcohol produces an ester molecule and a molecule of water

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This reaction is known as a condensation or esterification reaction

The ester functional group –COO– is similar to that of a carboxylic acid, except that the H atom of the carboxyl group has been replaced by a hydrocarbon branch.

Esters are responsible for natural and artificial fragrance and flavourings in plants and fruits.

In naming an ester you have to recognize that an ester has 2 distinct parts. The main part contains the C=O group which comes from the parent acid. The second part is the alkyl group.

Naming Esters

1. Identify the main part of the ester, which contains the C=O group. This part comes from the parent acid.

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2. Begin by naming the parent acid but replace the –oic acid ending of the name with –oate. (propanoic acid becomes propanoate)

3. The second part is the alkyl group that is attached to the single oxygen atom. Name this as you would any other alkyl group (in this case = methyl)

4. Put the names together. Note that esters are named as two words.

Name the following ester and the acid and alcohol from which it can be prepared.

Name the following ester and the acid and alcohol from which it can be prepared

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Lesson 7 homework

h


Organic Reactions

Summary and Review of all organic molecules

Full Naming Quiz (in two days)

Review – Functional Groups Physical Properties of Hydrocarbon Derivatives

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Halides higher boiling points than hydrocarbons (1-12Cs are liquids at SATP) due polarity of many of the molecules

Even though these molecules are polar, they are insoluble in water as they are more attracted to themselves then the water molecules.

Alcohols Much higher boiling points than hydrocarbons (1-12Cs are liquids at SATP) due to hydrogen bonding between hydroxyl groups of adjacent molecules

Small alcohols are totally miscible in water, but the larger the hydrocarbon part of the alcohol (nonpolar part), the more nonpolar the alcohol is

Carboxylic Acids

Like alcohols they have hydrogen bonding, but is more significant due to the C=O. This means greater bps and solubility than alcohols with same number of Cs.

Carboxylic acids with 1-4Cs are

completely miscible in water, but like alcohols decrease as the non-polar end gets larger

Compound Boiling Point (oC)

butane -0.5

butan-1-ol 117.2

butanoic acid 165.5

Esters Fruity odour in some cases

Polar but they lack the –OH bond therefore do not have hydrogen bonding, so lower bps than both alcohols and carboxylic acids

Esters with few carbons are polar enough to be soluble in water

HYDROCARBON DERVIVITIVES SUMMARY TABLE

Hydrocarbon Description Example(s)

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(General Formula)Organic Halides

Alcohols

Carboxylic Acids

Esters

Hydrocarbon Reactions:

Addition, Substitution and Elimination

Today’s Objectives: Section 10.2,10.3 and 10.4 (pg. 419-444)

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1) Define, illustrate and provide examples of simple addition, substitution, elimination and esterification (condensation)

2) Predict products and write and interpret balanced equations for the above reactions

Hydrocarbon Reactions

1. Addition

alkenes and alkynes + H2(g) alkanes (hydrogenation)

alkenes and alkynes + HX (or X2) organic halides

2. Substitution

alkanes and aromatics + X2 organic halides

3. Elimination

alcohols alkenes + water (dehydration)

organic halides + OH- alkenes + halide ion + water

4. Esterification (already covered, just review)

carboxylic acid + alcohol ester + water

5. Polymerization – monomer + monomer = polymer

addition and condensation

1. Addition Reactions: reaction of alkenes and alkynes with hydrogen gas, a halogen compound, a hydrogen halide compound or water.

Addition reactions usually occur in the presence of a catalyst

Changes the saturation of the molecule (unsaturated → saturated)

a) Addition with H2(g) (also called hydrogenation)

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b) Addition of a halogen

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c) Addition of an HX (hydrogen halide) molecule

Show both possible isomers when predicting the products

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d) Addition of water an alkene

Practice Addition Reactions

For each of the following questions, draw condensed structural diagrams and name all products

1. ethene + bromine

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2. hydrogen chloride + ethene

3. 3-methylbut-1-yne + excess hydrogen

4. Pent-2-ene + water

2. Substitution Reactions – breaking of a C-H bond in an alkane or an aromatic ring and replacing it with another atom or group of atoms

Usually occur slowly at room temperature, so light may be necessary as a catalyst

Often substitutes a halogen for a hydrogen

No change in saturation (saturated → saturated)

2. Substitution Reactions – breaking of a C-H bond in an alkane or an aromatic ring and replacing it with another atom or group of atoms

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Practice Substitution Reactions

For each of the following questions, draw condensed structural diagrams and name all products

1. propane + fluorine

2. ethane + chlorine

3. Elimination Reactions – involves eliminating atoms or groups of atoms from adjacent carbon atoms; decreases the level of saturation

a) Alkane cracked into an alkene (uses high temperatures)

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Benzene rings are stable, like alkanes, so they react slowly with halogens, even in the presence of light.

As with alkanes, further substitution can occur in benzene rings, until all hydrogen atoms are replaced by


b) Alcohol is reacted with a catalyst to produce an alkene and water (dehydration – removes a water molecule from the alcohol)

c) Alkyl halide reacts with a hydroxide ion (OH-) to produce an alkene (dehydrohalogenation – removes a hydrogen and halogen atom)

Practice Elimination Reactions

1. Write a structural formula equation for the preparation of but-2-ene from chlorobutane, in the presence of a strong base

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2. Write a structural formula equation for the preparation of but-2-ene from butan-2-ol

Reaction type

Complete Combustion

Addition Elimination Substitution Esteri-fication

Reactants

Products

Other

Other

Day 8 Homework

Pg. 422 #7,8 (Addition and Substitution)

Pg. 433 #18-19 (Elimination)

Pg. 443 #1, 5-8 (Esterfication)


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Polymerization

STS Connections

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Organic Chemistry:

Polymerization Reactions

Today’s Objectives: Section 10.5 (pg. 445-459)

1) Define, illustrate, and give examples of monomers, polymers, and polymerization in living and non-living systems

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STS: 2) Illustrate how science and technology are developed to meet societal needs and expand human capabilities

STS: 3) Illustrate how science and technology have both intended and unintended consequences

Polymerization

Polymers are large molecules made of chains of monomers, small molecules that link together.

Polymerization is the formation of polymers from these small units

Polymers can occur naturally (proteins, carbohydrates) and can be synthesized (nylon, Teflon, polyethylene)

They play an integral part in the function of life systems and have revolutionized the way society functions

Addition Polymerization

Many plastics (synthetic polymers) are made by this process

The polymerization process is initiated with a free radical (a species with an unpaired electron). The free radical attacks and breaks the double bond forming a new free radical that attacks another monomer

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Addition Polymerization always results in one product, the polymer

Requires unsaturated hydrocarbon monomers and bond saturation occurs when the polymer is made

Common polymers produced by addition polymerization:

Things to know about addition polymers…

The polymer names end in –ene (i.e. polystyrene, polypropene). Does this mean they have double bonds?

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What properties make Teflon a good product for non-stick materials?

Condensation Polymerization

Monomers combine to form a polymer and a bi-product. Each time a bond forms between monomers, small molecules, such as water, ammonia, or HCl are “condensed” out.

The polymerization of nylon:

Condensation polymerization also produces natural polymers, called proteins.

Amino acids (monomers) polymerize to make peptides (short chains of amino acids) or proteins (long chains of amino acids)

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Comparison of Addition and Condensation Polymerization

Polyester

When a carboxylic acid reacts with an alcohol in an esterification reaction, a water molecule is eliminated and a single ester molecule is formed.

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Addition Condensation


This esterification reaction can be repeated so many esters are joined in a long chain… a polyester

This is created using a dicarboxylic acid (an acid with a carboxyl group at each end) and a diol (an alcohol with a hydroxyl group at each end)

The ester linkages are formed end to end between alternating acid and alcohol molecules

Polyester: Dacron

Another example of a polyester:

Note the two carboxyl groups in the dicarboxylic acid and the two hydroxyl groups in the polyalcohol that start the chain reaction

Most synthetic polymers have a natural counterpart

Starch, wood, silk, DNA

Day 9 Homework

Pg. 448 #2-4

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Pg. 452 #13

Pg. 455 #16, 17

Due tomorrow


Labs ?

Chapter 10 Exam

Assignment #2 Due

KIM Sheets

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