Unit 2(b) Esters, Fats And Oils

Question 1

How are esters formed?

Answer 1

Condensation reaction between an alcohol and a carboxylic acid

Question 2

What molecule is eliminated when an ester is formed?

Answer 2

Water

Question 3

How are esters named?

Answer 3

First word - parent alcohol, ends in -YL

Second word - parent acid, ends in -OATE

Question 4

What is the catalyst for the production of esters?

Answer 4

Concentrated sulphuric acid

Question 5

Why is a cold paper towel used in the production of esters?

Answer 5

Acts as a condenser

Question 6

How can an ester be detected?

Answer 6

Immiscible layer on the surface of the solution

Characteristic sweet smell

Question 7

What are some uses of esters?

Answer 7

Flavourings, solvents, perfumes

Question 8

How can esters be broken back down into their parent alcohol and acid?

Answer 8

Hydrolysis

Question 9

What is the formula for an ester link?

Answer 9

-COO (one O is double bonded)

Question 10

Why are there high concentrations of esters in the air?

Answer 10

Esters are volatile

Question 11

What does VOC stand for?

Answer 11

Volatile Organic Compounds

Question 12

What are fats and oils examples of?

Answer 12

Esters

Question 13

What are some properties of fats and oils?

Answer 13

Concentrated source of energy
Slow release of energy
Greasy
Used as fuels and lubricants for agricultural machinery

Question 14

What 3 groups can fats and oils be classified as?

Answer 14

Animal source
Vegetable source
Marine source

Question 15

What problems are associated with fats and oils in the diet?

Answer 15

(Saturated) fats are linked to heart disease

However, some essential vitamins are only found in fatty foods

Question 16

What molecules are fats and oils formed from?

Answer 16

Glycerol and 3 carboxylic acid molecules - fatty acids

Question 17

What is glycerol?

Answer 17

Propane-1,2,3-triol (glycerol) is a triol, so 3 -OH groups are present

Question 18

How many ester links does a fat/oil molecule have?

Answer 18

3

Question 19

What is produced on the hydrolysis of fats and oils?

Answer 19

Fatty acids and glycerol at a ratio of 3:1

Question 20

Why do saturated fats have higher melting and boiling points than unsaturated fats?

Answer 20

Saturated molecules have no double bonds, so can pack closely together, allowing maximum LDF.
Unsaturated molecules are bent at the double bonds, and so are unable to pack together, resulting in less LDF so a lower melting point

Question 21

Do fats and oils decolourise bromine?

Answer 21

Oils do, fats don’t

Question 22

How can oils be converted into fats?

Answer 22

Hydrogenation

Question 23

What is ‘hardening’?

Answer 23

The process by which unsaturated oils are made more saturated, creating healthier spreads such as margarine

Question 24

What is hydrogenation?

Answer 24

Addition of hydrogen

Question 25

What is dehydrogenation?

Answer 25

Removal of hydrogen

Question 26

What is hydration?

Answer 26

Addition of water

Question 27

What is dehyration?

Answer 27

Removal of water

Question 28

What is condensation?

Answer 28

Formation of 1 large molecule from 2 smaller molecules with the removal of water

Question 29

What is hydrolysis?

Answer 29

Splitting of 1 large molecule into 2 smaller molecules using water