Some Families of Organic Compounds

When does tetrahedral geometry only occur?

Saturated compounds with four single bonds

Name two types of compounds that are tetrahedral?

Chloroalkanes. Alcohols

Chloroalkane (definition)

A compound in which one or more of the hydrogen atoms in an alkane have been replaced by chlorine atoms

Draw chloromethane

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Draw trichloromethane

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Draw 1,2-dichloropropane

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Uses of chloroalkanes

Industrial solvents e.g. dry cleaning

In what solvents are chloroalkanes soluble in?

Non polar solvents

What form are chloroalkanes in at room temperature?

Liquid

Functional group (definition)

An atom or group of atoms which are responsible for the characteristic properties of an organic compound or a series of organic compounds

Functional group of alcohols

OH

What kind of bonding is between O and H?

Hydrogen bonding

Draw ethanol

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Draw methanol

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Draw propan-2-ol

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Primary alcohol (definition)

An alcohol where the carbon atom bonded to the OH group is bonded to 1 other carbon

Draw a primary alcohol

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Secondary alcohol (definition)

An alcohol where the carbon atom bonded to the OH group is bonded to 2 other carbons

Draw a secondary alcohol

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Tertiary alcohol (definition)

An alcohol where the carbon atom bonded to the OH group is bonded to 3 other carbons

Draw a tertiary alcohol

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Use of ethanol/alcohols

Found in alcoholic drinks

How is ethanol made?

Fermenting glucose using yeast

Equation for fermentation

C6H12O6 → 2CH5OH +2CO2

Do alcohols have higher or lower boiling points than their corresponding alkanes e.g. ethanol and ethane?

Higher

Why do alcohols have higher boiling points than their corresponding alkanes?

Due to the hydrogen bonding between the O and the H

What is added to prevent people from drinking industrial ethanol?

Methanol

Why does methanol prevent people from drinking industrial ethanol?

Methanol is toxic

What happens to ethanol after methanol is added and what’s it now called?

Becomes denatured and is known as methylated spirits

Are alcohols soluble in water?

Only small alcohol molecules. Larger ones are soluble on non-polar solve ts

Why are only small alcohol molecules soluble in water?

Hydrogen bonding between O and H. Effect of hydrogen bonding decreases as molecule gets larger

What is a planar carbon?

A carbon with planar geometry

In what type of molecules does planar geometry occur in?

Unsaturated

Name 5 types of planar compunds

Aldehydes. Ketones. Carboxylique acids. Esters. Benzene/natural compounds with benzene

Functional groups of aldehydes

CHO

What name ending are given to the compounds of Aldehydes?

“Al”

Where are double bonds located in aldehydes?

The edge

What part of aldehydes is polar

The double CO bond

What shape is the rest of the aldehyde (C-H)?

Tetrahedral

What is a carbonyl group?

C = O

Draw methanal

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Draw propanal

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Boiling points of aldehydes compared to alkanes

Boiling points of aldehydes are higher than the respective alkanes

Why do aldehydes have higher boiling points than their respective alkanes?

Dipole-dipole forces between the aldehyde molecules are stronger than weaker Van-der-Waals forces between alkane molecules

Boiling points of aldehydes compared to corresponding alcohols

Boiling points of aldehydes are lower than their corresponding alcohols

Why do aldehydes have higher boiling points than their respective alcohols?

Dipole-dipole forces in aldehydes are weaker than hydrogen bonding in alcohols

Are aldehydes soluble in water? Why?

Only small molecules are soluble because of the polar carbonyl group

Name an aromatic aldehyde

Benzaldehyde

Draw benzaldehyde

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What does benzaldehyde smell like?

Almonds

Where is benzaldehyde found?

Almond kernels

What is benzaldehyde used as?

Flavouring agent

Functional group of ketones

CO

Name ending for ketones

One

Draw propanone

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Draw butan-2-one

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What is propanone also known as?

Acetone

What is propanone used for?

Nail polish remover

Where is the carbonyl group located on ketones?

On a central carbon

What kind of intermolecular forces do ketones have?

Dipole-dipole

Boiling points of ketones are … than their respective alkanes

Higher

Why are the boiling points of ketones higher than their corresponding alkanes?

Dipole-dipole forces (ketones) are stronger than the Van-der-Waals forces (alkanes)

Boiling points of ketones are … than their respective alcohols

Lower

Why are the boiling points of ketones lower than their corresponding alcohols?

Dipole-dipole forces (ketones) are weaker than hydrogen bonding (alcohols)

Are ketones soluble in water? Why?

Small molecules are soluble in water due to the polar carbonyl group. Larger the ketone molecule the less soluble due to the effect of the carbonyl group decreasing

Corresponding aldehydes and ketones are … (e.g. propanol and propanone)

Structural isomers

Carboxylic acid functional group

COOH

Name ending of carboxylic acids

oic acid

Where is the COOH located on carboxylic acids?

End of the molecule at the same carbon

Draw ethanoic acid?

…

What acid is found in nettle and ant stings?

Methanoic/formic acid

What is ethanoic/acetic acid used for (2)?

Flavouring agent in vinegar. Makes cellulose acetate (camera film)

Use of propanone acid and benzoic acid?

Preservatives in food

What kind of bonding do carboxylic acid molecules have?

Hydrogen bonding

Boiling points off carboxylic acid are … than their respective alkanes, aldehydes, alcohols and ketones. Why?

Higher. Strong hydrogen bonding between the carboxylic acid molecules are stronger than the Van-der-Waals and Dipole-Dipole forces between the others

Are carboxylic acid molecules soluble in water? Why?

Small carboxylic molecules are soluble. Longer the carbon chain, the less soluble the carboxylic acid is in water due to the effect of the hydrogen bonding decreasing

Functional group of esters

COOC

Name ending for esters

“-yl -oate”

How to get the chemical formula of an ester from an alcohol and a carboxylic acid?

Drop H from carboxylic acid. Drop OH from alcohol

How are esters formed?

Alcohol and carboxylic acid are reacted with sulphuric acid used as a catalyst

What kind of reaction is the formation of an ester?

Condensation reaction

Why is the formation of esters called a condensation reaction?

Loss of a water molecule

Process of naming an ester

Identify which part is from the carboxylic acid and which is from the alcohol. Name the section from the alcohol first. Name carboxylic acid and change the “oic acid” to ”oate”. Combine names.

What are esters used as?

Flavourings and fragrances because they have sweet, fruity scents

What kind of organic compounds are fats and oils?

Esters

What kind of intermolecular forces do esters have? Why?

Dipole-dipole due to the carbonyl group

Are esters soluble in water? Why?

Small esters are soluble because of the Dipole-Dipole forces. The longer the carbon chain, the less soluble due to a decrease of the effect of the C = O.

Are fats and oils soluble in water? Why?

Insoluble as they are large esters

Why is there a ring in aromatic compounds?

Positions of double bonds aren’t fixed

Why are the electrons in a benzene ring delocalised?

The three pi bonds of the three double bonds in the benzene ring are shared and move from carbon to carbon

Evidence for aromatic compounds being stable?

Bond lengths between carbon atoms are identical

What do aromatic compounds contain?

Benzene ring

What are organic natural products?

Compounds made in nature that contain benzene rings

Examples of organic natural products

Cocaine (lab). Paracetamol (lab). Eugenol (clove oil) (natural)

Draw ethylbenzene

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Draw methyl ethanoate

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Draw ethyl methanoate

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Why is only a small amount of benzene used in petrol despite it improving petrol’s octane number?

Carcinogenic

How many electrons does a benzene molecule have?

42

How many electrons in a benzene molecule are involved in hydrogen bonding?

12