General

Question 1

Suggest 2 advantages of using calcium carbonate to reduce the acidity of soil

Answer 1

• does not wash away as it is insoluble
• does not increase the pH above 7
• it is naturally occurring / does not need to be processed

Question 2

Explain the chemistry of desulfurisation of flue gasses

Answer 2

Any 3 from:

• flue gas contains sulfur dioxide
• sulfur dioxide is acidic
• calcium carbonate reacts with sulfur dioxide
• to make a salt (calcium sulfite) / neutralisation

Question 3

Give the uses of calcium carbonate

Answer 3

• desulfurisation of flue gas (SO2)
• making steel or iron in the blast furnace
• making cement
• treating acidic rivers/ lakes
• chalk

Question 4

Explain what is meant by the term fossil fuel

Answer 4

• burnt to release energy

- take a long time to form (from organic materials

Question 5

Explain how combustion of coal can form sulfuric acid

Answer 5

• oxygen and sulfur from fuel reacts to
• form sulfur dioxide
• sulfur dioxide reacts with air and water to form sulfuric acid

(3 marks)

Question 6

Explain how high temperatures generated by the combustion of fossil fuels can lead to the formation of nitric acid

Answer 6

• oxygen and nitrogen react
• making oxides of nitrogen
• it reacts with water to make nitric acid

Question 7

Name the gasses that can reduce copper (II) oxide to copper

Answer 7

• hydrogen
• carbon monoxide
• ammonia
• methane

(More reactive than copper)

Question 8

Propane is C3H8. Give an equation for the complete combustion of propane

Answer 8

C3H8 + 5O2 -> 3CO2 + 4H2O

Question 9

Name 2 harmful effects of acid rain

Answer 9

• acidifies lakes and rivers, killing fishes
• reduces fertility in soil
• attacks limestone buildings and statues

Question 10

Ethanoic acid is a strong or weak acid?

Answer 10

Weak acid

Question 11

Explain what is meant by the term weak base

Answer 11

• it is a proton acceptor

- it does not accept protons readily