Alcohols, carboxylic acids and esters.

Question 1

What are alcohols?

Answer 1

Carbon-based molecules that contain the functional group -OH. They are a homologous series.

Question 2

What is the general formula for alcohols?

Answer 2

Cn H2n+1 O H

Question 3

What are four properties of alcohols?

Answer 3

1. They dissolve in water to form neutral solutions.
2. They react with sodium to produce hydrogen.
3. They burn in air.
4. They are used as fuels and solvents.

Question 4

What alcohol do alcoholic drinks contain?

Answer 4

Ethanol.

Question 5

How can ethanol be turned to ethanoic acid?

Answer 5

Ethanol can be oxidised to ethanoic acid either by chemical oxidising agents or by microbial action.

Question 6

What is the main acid in vinegar?

Answer 6

Ethanoic acid.

Question 7

What are carboxylic acids?

Answer 7

Carbon based molecules that contain the functional group -COOH.

Question 8

What is the general formula for carboxylic acids?

Answer 8

Cn H2n+1 C O O H

Question 9

What are three properties of carboxylic acids?

Answer 9

1. They dissolve in water to form acidic solutions.
2. They react with carbonates (e.g. sodium carbonate) to produce carbon dioxide.
3. They react with alcohols (in the presence of an acid catalyst) to form esters.

Question 10

Why are carboxylic acids called weak acids?

Answer 10

Because they don’t dissociate fully in water.

Question 11

What has a higher pH, aqueous solutions of weak acids or aqueous solutions of strong acids with the same concentration?

Answer 11

Aqueous solutions of weak acids.

Question 12

How are esters formed?

Answer 12

By alcohol and carboxylic acids reacting together.

Question 13

What ester is formed when ethanol and ethanoic acid react together?

Answer 13

ethyl ethanoate.

Question 14

What is the functional group of esters?

Answer 14

-COO

Question 15

What is the functional group of alcohols?

Answer 15

-OH

Question 16

What is the functional group of carboxylic acids?

Answer 16

-COOH

Question 17

What is a property of esters?

Answer 17

They are volatile compounds.

Question 18

What does volatile mean?

Answer 18

A low boiling point.

Question 19

What can esters be used for?

Answer 19

1. In perfumes.

2. As flavourings in food.

Question 20

Why are esters used in perfumes and as flavourings in food?

Answer 20

Because they have distinctive smells.

Question 21

What functional group do all alcohols contain?

Answer 21

-OH

Question 22

Do alcohols dissolve in water to form a neutral solution?

Answer 22

Yes

Question 23

Do alcohols react with sodium to produce carbon dioxide?

Answer 23

No

Question 24

Do alcohols burn in air?

Answer 24

Yes

Question 25

What is the name of the carboxylic acid with the formula C2H3COOH?

Answer 25

Ethanoic acid.

Question 26

Give two uses of esters.

Answer 26

1. Perfumes.

2. Food flavourings.