1 The hydrogen needed for the manufacture of ammonia is made by a process called

steam reforming.
In this process, a mixture of methane and steam is passed over a nickel catalyst.
The equation for the reaction is

CH4(g) + H2O(g) U CO(g) + 3H2(g) ǻH = + 210 kJ/mol

(a) In this part of the question, assume that the reaction reaches a position of equilibrium.
(i) Predict whether a high or low temperature would produce the highest yield of hydrogen.
Give a reason for your choice.
(1)

prediction ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . .

reason ........................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . .

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(ii) Predict whether a high or low pressure would produce the highest yield of hydrogen.
Give a reason for your choice.
(1)

prediction ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ........................................................................................................................................... . . . . . . . . . . . . . . . . . . . . . . . . . .

reason ........................ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . .................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . .

(b) Explain how a catalyst increases the rate of a reaction.

(2)

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. . . . . . .................................... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ............................................................................................................................................ . . . . . . . . . . . . . . . . . . . . . . . . . .

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 (c) Some of the carbon monoxide produced is removed in another reaction.
In this reaction, carbon monoxide is mixed with steam and passed over a heated catalyst.
The reaction is reversible and the carbon monoxide is oxidised to carbon dioxide.
(i) Write a chemical equation for this reaction.
(2)

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(ii) Explain why the carbon in carbon monoxide is oxidised in this reaction.
(1)

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(iii) The carbon dioxide produced can be removed by passing the gas through a
solution of potassium carbonate, K2CO3
The potassium carbonate reacts with carbon dioxide and water to form
potassium hydrogencarbonate, KHCO3
Write a chemical equation for this reaction.
(2)

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(Total for Question 1 = 9 marks)

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