Functional Groups

Question 1

What is the functional group of alcohols?

Answer 1

-OH.

Question 2

What is the general formula of alcohols?

Answer 2

Cn H2n+1 OH

Question 3

What are the first three alcohols?

Answer 3

Methanol, ethanol and propanol.

Question 4

What is a homologous series?

Answer 4

A group of chemicals that react in a similar way because they have the same functional group.

Question 5

What do the first three alcohols burn in air to produce?

Answer 5

Carbon dioxide and water.

Question 6

What do the first three alcohols dissolve in water to produce?

Answer 6

Neutral solutions.

Question 7

What do the first three alcohols react with sodium to give?

Answer 7

Hydrogen and alkoxides.

Question 8

What is the main alcohol in alcoholic drinks?

Answer 8

Ethanol.

Question 9

Why are alcohols useful solvents?

Answer 9

They can dissolve most compounds that water can, and more.

Question 10

What is the solvent in perfumes and aftershave lotions?

Answer 10

Ethanol.

Question 11

What is methylated spirit used for?

Answer 11

1. Cleaning paint brushes

2. Fuel

Question 12

What is ethanol used as a fuel for?

Answer 12

1. Spirit burners (clean, no odour)

2. Car fuel

Question 13

Why is ethanol good as a car fuel?

Answer 13

1. Clean burning, less pollution.
2. Renewable
3. Good for countries without oil

Question 14

What functional group do carboxylic acids have?

Answer 14

-COOH.

Question 15

What are the first three carboxylic acids?

Answer 15

Methanoic acid, ethanoic acid and propanoic acid.

Question 16

What is the equation for the reaction between carboxylic acids and carbonates?

Answer 16

Carboxylic acid + Metal carbonate –> Carbon dioxide + Water + Metal carboxylic-anoate

e.g Ethanoic acid + Sodium carbonate –> Carbon dioxide + Water + Sodium ethanoate

Question 17

Why don’t carboxylic acids form strong acidic solutions?

Answer 17

They don’t ionise completely, so not many H+ ions are released.

Question 18

What is the strength of an acid dictated by?

Answer 18

How well it has ionised in water.

Question 19

How can ethanoic acid be made?

Answer 19

By oxidising ethanol.

Question 20

What is the equation for the oxidisation of ethanol?

Answer 20

Ethanol + Oxygen –> Ethanoic acid + Water

Question 21

How can ethanoic acid be fermented?

Answer 21

1. Yeast

2. Oxidising agents

Question 22

What can ethanoic acid be used for?

Answer 22

Dissolved in water to make vinegar.

Question 23

What can citric acid be used for?

Answer 23

1. Fizzy drinks

2. Removing scale

Question 24

What are carboxylic acids used for?

Answer 24

1. Soaps and detergents (long chain)

2. Preparation of esters

Question 25

Why isn't ethanoic acid usually chosen as a solvent?

Answer 25

It makes the solution acidic.

Question 26

What are esters formed from?

Answer 26

An alcohol and a carboxylic acid.

Question 27

What is the equation for the formation of esters?

Answer 27

Alcohol + Carboxylic acid --> Ester + Water

Question 28

What kind of catalyst is used in the formation of esters?

Answer 28

Acid catalyst e.g concentrated sulfuric acid

Question 29

What property of esters makes them good for what purpose?

Answer 29

Esters are volatile so they're good for perfumes, flavourings and aromas.

Question 30

What are the problems with esters?

Answer 30

1. Flammable 2. Don't mix well with water 3. Inhaling the fumes irritates mucous membranes 4. Can be toxic

Question 31

What do esters mix with?

Answer 31

Alcohols and organic solvents.

Question 32

What are esters used for?

Answer 32

1. Solvents for paint, ink, glue and nail varnish remover 2. Ointments 3. Perfumes, flavourings etc.

Question 33

Why can esters result in flash fires?

Answer 33

They're heavier than air and flammable.