Figure 6 shows a flow diagram for the Haber process - AQA - GCSE Chemistry - Question 6 - 2016 - Paper 3
Question 6
Figure 6 shows a flow diagram for the Haber process.
Nitrogen gas
Hydrogen gas
Reactor containing iron
Mixture of gases
(nitrogen, hydrogen and ammonia)
6 (a) (... show full transcript
Worked Solution & Example Answer:Figure 6 shows a flow diagram for the Haber process - AQA - GCSE Chemistry - Question 6 - 2016 - Paper 3
Step 1
Hydrogen gas is obtained from methane. Name one source of methane.
96%
114 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
A source of methane is natural gas.
Step 2
Suggest why air must not get into the reactor.
99%
104 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Air contains oxygen, which would react with and oxidize the hydrogen, affecting the reaction efficiency.
Step 3
Describe what happens to the mixture of gases from the reactor.
96%
101 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The mixture of gases is cooled. Ammonia condenses or liquefies and can be separated, while nitrogen and hydrogen remain as gases and are returned to the reactor.
Step 4
Use Figure 7 to suggest the conditions that produce the greatest yield of ammonia.
98%
120 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The greatest yield of ammonia occurs at a temperature of 200 °C and a pressure of 1000 atmospheres.
Step 5
Use Figure 7 to suggest and explain why the conditions used to produce ammonia in the Haber process are a temperature of 450 °C and a pressure of 200 atmospheres.
97%
117 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
The reaction is reversible and exothermic; thus, lower temperatures decrease the yield of ammonia while higher temperatures increase the rate of reaction. The chosen conditions (450 °C and 200 atmospheres) balance the need for a reasonable yield with a fast reaction rate, while higher pressure increases yield but also energy costs.
