Mini-Mock Unit 3 Aqa Gcse Chemistry Higher Tier Worksheet Page 8
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18In the industrial process a mixture of nitrogen and
hydrogen is passed over iron at a temperature of about
450 °C and 200 atmospheres pressure.
(a)
Use the graph to find the percentage of
ammonia present when the temperature and pressure
are 450 °C and 200 atmospheres.................. %(2)
(b)
Explain why the nitrogen and hydrogen
mixture is passed over iron. (2)
(c)
Explain, as fully as you can, using the graph
and your knowledge of the Haber process why 450 °C and
200 atmospheres were chosen as conditions for this
process. (8)(Total 12 marks)
Q17.
The reaction of methane with steam is used in industry to make hydrogen.
(a)
One of the reactions in this process is represented by this equation.
CH
(g)
+
H
O
CO (g)
+
3H
(g)
4
2
2
The forward reaction is endothermic.State the conditions of temperature and pressure that would give the
maximum yield of hydrogen.
Explain your answers.
(i)
Temperature (2)
(ii)
Pressure (2)
(iii)
Which one of the following metals is most likely to be a catalyst for this process? Draw a ring around
your answer.
aluminium
lead
magnesium
nickel
sodium
Give a reason for your choice. (1)
(b)
A second stage in this process is represented by this equation.
(i)
Use the bond energies given in the table to help you to calculate the nett energy transfer (energy
change) for this reaction.
Bond
Bond energy in kJ/mol
Nett energy transfer =
...................................... kJ/mol(3)
C
1077
C = O
805
(ii)
State whether this reaction is
exothermic or endothermic.Explain, by
H – H
436
reference to your calculation, how you
know. (2)
(Total 10 marks)
O – H
464
Page 8
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