Organic Chemistry

Question 1

Explain the fermentation process of alcohols,wine and the advantages/disadvantages of

Answer 1

Extract glucose from crops
Add yeast to the glucose (enzymes in the yeast act as a catalyst)
Fermentation takes place at 30-40 degrees
It is a batch process
Carbon dioxide is released
Advantages-
More carbon neutral
Cheap equipment needed for the Batch process
Sugars used are a renewable source

Disadvantages-
It takes time (time consuming) very slow process
Batch process has high labor costs
Very impure so it needs fractional distillation which takes time and is expensive.

Question 2

Why is fermentation an anaerobic process?

Answer 2

Because oxygen is not required in the production of ethanol during fermentation.

Question 3

What is the process of the Hydration of ethene? What are the advantages and disadvantages?

Answer 3

1- extracting crude oil from the ground
2- crude oil will be placed in the fractional distillation and cracking to get ethene
3- ethene is then hydrated (phosphoric acid is used as the catalyst, high temperatures and pressure is used)

Advantages-
Pure product
Fast reaction
Continuous ( cheaper manpower)

Disadvantages-
High energy is used which can be expensive (high temperature and pressure)
High costs for the equipment needed
Ethene is non renewable

Question 4

Why is Ethanoic acid a weak acid?

Answer 4

Because it’s a carboxylic acid, and every 3 molecules only 1 is partially ionised which makes carboxylic acids including ethanoic acid to be weak due to partial ionisation.

Question 5

Why do carboxylic acids make the solutions acidic?

Answer 5

When ionisation is complete, H+ ions are released

Question 6

How can ethanol turn into ethanoic acid? And by what?

Answer 6

Ethanol can be oxidised to ethanoic acid by chemical oxidising agents

Question 7

What are the functional group that you need to add to the structures of carboxylic acids, esters, alcohols-

Answer 7

OH- = alcohol
COOH = carboxylic acids
COO = esters

Question 8

What do carboxylic acids react with? What do they produce whilst reacting?

Answer 8

React with carbonates to produce carbon dioxide, hydrogen, and a salt

Question 9

Explain why the solution of Ethanoic acid has a different PH than hydrochloric acid-

Answer 9

Ethanoic is a weak acid ( less acidic than hydrochloric acid)
Ethanoic acid does not ionise completely in water
Less H+ ions produced
So Ethanoic acid will have a higher PH than HCL since it is weaker

Question 10

State two uses of esters-

Answer 10

Flavorings, perfumes (they give a nice scent)

Question 11

What needs to be reacted together to produce an ester?

Answer 11

Carboxylic acid and alcohol

Question 12

How can ethyl ethanoate be produced?

Answer 12

Ethanoic acid and ethanol

Question 13

What is the by product that is produced whilst reacting both alcohols and carboxylic acids to produce esters? What is the formula of that by product?

Answer 13

Water ( H2O)

Question 14

What needs to have the double bond connected to a carbon atom?

Answer 14

Oxygen needs to have a double bond connected to the carbon atom

Question 15

What is the catalyst used to produce esters? And is it a reversible reaction whilst producing esters?

Answer 15

Sulphuric acid is used. Yes since water and ester is able to form back into the alcohol and carboxylic acid.

Question 16

What are the root words for carboxylic acids, alcohols, esters: and give examples-

Answer 16

Carboxylic acids: -noic Ethanoic methanoic
Alcohols: -nol
Esters: -noate ethanoate, methanoate, propanoate

Question 17

What happens in a thermal decomposition reaction?

Answer 17

Heat is used to break down large/long molecules into shorter molecules

Question 18

What type of reaction uses thermal decomposition?

Answer 18

Cracking

Question 19

What does cracking produce?

Answer 19

Shorter hydrocarbon chain and an alkene

Question 20

What is a hydrocarbon?

Answer 20

A compound made from hydrogen and carbon

Question 21

Why is aluminum oxide or broken porcelain used in cracking?

Answer 21

They act as a catalyst which speeds up the rate of a reaction

Question 22

Cracking produces a mixture of products, this mixture contains hydrocarbons with different boiling points, what method can be used to separate this mixture?

Answer 22

Fractional distillation

Question 23

Why is cracking used in the oil industry? 3 marker

Answer 23

Cracking involves thermal decomposition which helps breakdown large molecules into smaller molecules by using heat. 1 mark

There is more large hydrocarbons being produced than needed, 1 mark
So cracking is used to increase the supply of smaller hydrocarbons since they flow more easily. 1 mark

Question 24

What is cracking used for? And where are they used?

Answer 24

To produce petrol for cars
To produce alkenes which is a raw material for the plastic industry
To produce hydrogen gas for the production of ammonia

Question 25

Compare between small hydrocarbons and large hydrocarbons-

Answer 25

Small hydrocarbons- low boiling points, easy to ignite (to heat), more volatile so they’re useful as fuels.
Large hydrocarbons- high boiling points, harder to ignite, less volatile so they’re useful not useful as fuels

Question 26

Where are the large hydrocarbons being produced? What is used to make them smaller?

Answer 26

From fractional distillation large hydrocarbons are produced, cracking is used to produce smaller hydrocarbons since they’re much more useful.

Question 27

Other people say that increasing the production of ethanol from sugar cane will be
bad for the environment.
Suggest two reasons why.

Answer 27

Production of ethanol will cause a destruction of habitats to grow the crops.

Production plants for ethanol causes visual pollution

Question 28

Compounds A and B are both colourless liquids.
A test tube contains a colourless liquid, which could be either compound A or
compound B.
Describe a simple chemical test to show which compound, A or B, is in the test tube.

Answer 28

Add hydrogen carbonate.
If the test tube contained compound A, carbon dioxide will be released.
If the test tube contained compound B, carbon dioxide will not be released.