C14. Organic Chemistry

Question 1

Homologous series

Answer 1

A ‘family’ of similar compounds with similar properties due to the presence of the same functional group

Question 2

Structural isomers

Answer 2

Compounds with the same molecular formula but different structural formula

Question 3

Polymers

Answer 3

Large molecules built up from small units (monomers)

Question 4

Why is ethanoic acid described as weak?

Answer 4

Ethanoic acid ionises partially

Question 5

6 characteristics of a homologous series

Answer 5

1. same/similar chemical properties
2. same general formula
3. consecutive members differ by CH2
4. same functional group
5. common methods of preparation
6. physical properties vary in predictable manner / gradually change

Question 6

3 advantages of producing ethanol by the catalytic addition of steam to ethene

Answer 6

1. purer product
2. faster reaction
3. continuous process

Question 7

2 disadvantages of producing ethanol by the catalytic addition of steam to ethene

Answer 7

1. Uses non-renewable sources

2. Expensive (more heat is needed to make steam and keep the reaction running at 220°C-350°C)

Question 8

3 advantages of producing ethanol by the fermentation of glucose

Answer 8

1. renewable feedstock (carbohydrates are renewable)
2. lowER temperature means lowER energy costs
3. lowER pressure

Question 9

4 disadvantages of producing ethanol by the fermentation of glucose

Answer 9

1. A lot of land is needed to grow enough crops
2. Slow process
3. A lot of heat energy is required for fractional distillation
4. Yeast stops working when the % of ethanol reaches a certain level or if mixture becomes too warm

Question 10

3 reasons why the heating of ethanol (to ethanoic acid) is done using reflux

Answer 10

1. to ensure the volume of the mixture is maintained
2. to prevent the loss of volatile liquid
3. to ensure complete reaction with acidified potassium manganate (VII)
   * reflux = the method of retaining a volatile liquid from escaping into the atmosphere during heating

Question 11

6 pollution problems caused by non-biodegradable plastics

Answer 11

1. disposal will use up a lot of landfill space
2. raw materials are obtained from petroleum, thus depleting the supply of non-renewable sources
3. burning plastics releases pollutants and toxic gases harmful to health (eg. burning PVC releases hydrogen chloride gas)
4. improper disposal destroys the beauty of nature
5. improper disposal causes flash floods
6. improper disposal endangers wildlife

Question 12

Condensation polymerisation

Answer 12

Condensation
- 2 monomers joining
- with the removal of a small molecule
Polymerisation
- to form a large molecule / a long chain