9 Ammonia is manufactured from nitrogen and hydrogen by the Haber process.
N2(g) + 3H2(g)2NH3(g)
What is the percentage yield when 60 kg of ammonia is produced from 60 kg of hydrogen?
A
5.9%
B
17.6%
с
35.3%
D
50.0%

B

17.6%

Explanation:

1. Percentage yield = (Actual yield/theoretical yield) x 100

2. You know actual yield of ammonia (60kg) so you need to work out theoretical yield.

3. mols of hydrogen = m/mr = 60,000/2 = 30,000 mols.

4. 3:2 ratio so (30,000/3) x 2 = 20,000 mols of Ammonia.

5. Therefore mass of ammonia = mr x mols = 20,000 x 17 = 340,000 grams

6. So percentage yield is (60,000/340,000) x 100 = 17.6