s93qp3 Question 2d(i)
The detergents contain a bleach, sodium perborate, which removes coloured stains. There are chemicals, other than sodium perborate, that can bleach.
Name the gas that is used industrially to bleach paper. [1 mark]
answer: suphur dioxide or sulphur dioxide
s93 qp3 Question 3(d)(i)
Both sulphur and selenium have trioxides of the type XO3, which react with water to form acids.
Sulphur trioxide is used to make sulphuric acid. Give a large-scale use of this acid. [1 mark]
answer: making fertilisers
s93 qp3 Question 4(c)(ii)
Large amount of limestone are used in Europe to treat the smoke from coal-fired power station.
Name the acidic gas that is removed from the smoke, and explain why it should be removed.[2marks]
answers: sulphur dioxide, emission of sulphur dioxide to the air may dissolve in rain and resulting acid rain. (acid rain pH4, natural rain pH5.6)
w93 qp3 Question 5(a)(ii)
Zinc has been used for over two thousand years. The major ore is zinc blende, ZnS, which is mined in Canada, the USA and Australia.
Sulphur dioxide is formed during this extraction. Sulphur dioxide is used to preserve food.
Why does it slow down the rate at which food goes 'bad'? [1 mark]
answer: It kills bacteria.
s94 qp3 Question 5(b)(I)
One of the product of zinc extraction is sulphur dioxide. This is used to make sulphuric acid.
Most of the acid is neutralised to form ammonium sulphate.
What is the main use of ammonium sulphate? [ 1 mark]
answer: fertiliser
w94 qp3 Question 2 (b)
(i) Preservation E220 is sulphur dioxide.
How does it preserve food? [1 mark]
(ii) Sulphur dioxide can be made by burning sulphur in air.
Name a source of sulphur. [1 mark]
(iii) Why is sulphur dioxide used in the manufacture of wood pulp? [1 mark]
answers:
(i) by killing bacteria
(ii) underground deposits
(iii) for bleaching
s95 qp3 Question 5
Sulphuric acid is made by the Contact Process. The annual production in the UK is 3.5 million tonnes. The manufacture of fertilisers is the largest use for the acid.
In this process, sulphur dioxide is oxidised to sulphur trioxide, the rest is a product of the extraction of zinc.
i. What is one source of the element sulphur? [1 mark]
ii. Write a symbol equation for reversible reaction between sulphur dioxide and oxygen. [2 marks]
iii. Name the catalyst used in the Contact Process. [ 1 mark]
iv. Describe how sulphur trioxide is converted into concentrated sulphuric acid. [2 marks]
answers:
(i) sulpur deposits
(ii) SO2 + 1/2 O2 <=> SO3
(iii) Vanadium (V) oxide
(iv) by dissolving SO3 in water, while absorbing the evolving heat.
s96 qp3 Question 4c
Sulphuric acid is made from sulphur dioxide, air and water.
i. Write the equation for the reversible reaction that makes sulphur trioxide from sulphur dioxide. [2 marks]
ii. Describe how concentrated sulphuric acid is made from sulphur trioxide. [ 2 marks]
iii. Give one other scale use of sulphuric acid. [1 mark]
answers:
i. SO2 (g) + 1/2 O2 <===> SO3 (g)
ii. by dissolving SO3 (g) in concentrated H2SO4 to form oleum then add oleum to large quantities of water.
iii. making fertilizers
S96 qp3 Question 3 (e)
The reaction between sodium thiosulphate and hydrochloric acid produced small amounts of sulphur dioxide.
i. How is the gas made on large scale? [2 marks]
ii. State two industrial uses of sulphur dioxide. [2 marks]
answers:
i. by burning sulphur in air or roasting sulphide ores
ii. preserving food, preparation of sulphuric acid
s98 qp3 Question 2(a)(i)
Name a chemical, other than chlorine, that is used to bleach wood pulp. [1 mark]
answer: sulphur dioxide
s98 qp3 Question 4(b)
(i) Why is the Contact Process preferred to the older method of making sulphuric acid? [1 mark]
(ii) Sulphur dioxide is made by burning sulphur. Name a source of the element sulphur. [1 mark]
(iii) Name the catalyst used for the reaction between sulphur dioxide and oxygen. [1 mark]
(iv) what would be the effect of decreasing the temperature on the position of equilibrium in the reversible reaction between sulphur dioxide and oxygen? The forward reaction is exothermic.[2marks]
(v) In the older process, sulphur trioxide was reacted directly with water. Describe how the sulphur trioxide is changed into sulphuric acid in the Contact Process. [2 marks]
(vi) State two large-scale uses of sulphuric acid. [2 marks]
| answers: | (i) because it uses cheaper bstances. (ii) underground deposits. (iii) Vanadium(V) oxide. (iv) It will produce more SO3 (v) It is dissolved in sulphuric acid to form Oleum, which gives sulphuric acid by ilution. (vi) In fertilizer production and in detergent production. | |||
s99 qp3 Question 4a & c
| Sulphur production in the USA is about ten million tonnes per year. 90% of this sulphur is used to make sulphuric acid. | |||||||||
| (a) Sulphur dioxide is made by burning sulphur in air. Most of
it is used in the Contact Process. Give one other use of this gas.[1 mark] (c) In the Contact Process, sulphur dioxide is made by spraying molten sulphur into air. (i) Suggest why the molten sulphur dioxide is made by spraying molten sulphur into air. (ii) Describe how sulphur dioxide is changed into sulphur trioxide. [3 marks] (iii) Complete the equation for the formation of sulphuric acid from sulphur trioxide. [2 marks} SO3 + ........................... ----> H2S2O7 H2S2O7 + ........................... ----> .........H2SO4 (d) Over 50% of the sulphuric acid is used to make fertilisers such as the nitrogen-based fertiliser ammonium sulphate. i. Give one other use of sulphuric acid. answers: (a) bleaching (c) i. this increase the surface area and speed of reaction between sulphur and oxygen. ii. sulphur dioxide reacts with air at 400 to 450o with vanadium (V) oxide as catalyst.(V2O5). iii. SO3 + H2SO4 ----> H2S2O7 H2S2O7 + H2O ----> 2H2SO4 (d) Manufacture of detergents. |
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