This question is about ammonia and fertilisers - AQA - GCSE Chemistry - Question 2 - 2016 - Paper 2
Question 2
This question is about ammonia and fertilisers.
(a) Ammonia is produced by a reversible reaction.
The equation for the reaction is:
N₂ + 3H₂ ⇌ 2NH₃
Complete the ... show full transcript
Worked Solution & Example Answer:This question is about ammonia and fertilisers - AQA - GCSE Chemistry - Question 2 - 2016 - Paper 2
Step 1
Complete the sentence.
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
The forward reaction is exothermic, so the reverse reaction is endothermic.
Step 2
Calculate the percentage by mass of nitrogen in ammonia (NH₃).
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
To calculate the percentage by mass of nitrogen in ammonia, we first determine the molar mass of ammonia (NH₃). The formula is:
MNH3=(1imes14)+(3imes1)=17extg/mol
Next, we calculate the percentage by mass of nitrogen:
ext{Percentage of N} = rac{Mass ext{ of N}}{Total ext{ mass of NH}_3} imes 100 = rac{14}{17} imes 100 \\ \approx 82.35\%
Step 3
Give the pH of a neutral solution.
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
pH 7
Step 4
Which of these ionic equations shows a neutralisation reaction?
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
Tick the box for: H⁺ + OH⁻ → H₂O
Step 5
Name the salt produced when ammonia reacts with hydrochloric acid.
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 salt produced is ammonium chloride (NH₄Cl).
Step 6
Suggest how much ammonium nitrate farmers should use per hectare.
97%
121 rated
Only available for registered users.
Sign up now to view full answer, or log in if you already have an account!
Answer
Based on Graphs A, B, and C:
Graph A indicates that crop yield increases up to a certain point with the addition of ammonium nitrate and then levels off, suggesting wastage beyond that point.
Graph B indicates profit maximization occurs with a certain range of ammonium nitrate.
Graph C shows that the run-off increases significantly past a specific mass, potentially harming the environment.
Farmers should consider using around 200 kg per hectare, as this appears to yield good results without excessive run-off or wasting resources.
