The Haber Process for the production of ammonia is represented by: 3 H₂(g) + N₂(g) → 2 NH₃(g)
If a mixture of 30 g of hydrogen with 10 g of nitrogen produced 8.4 g of ammonia, what was the percent yield?

Question

Quizplus · Accepted Answer

First, we need to calculate the theoretical yield of ammonia using stoichiometry. From the equation, we can see that the ratio of H2 to NH3 is 3:2, so we need to find the limiting reactant first.

The moles of hydrogen present in the mixture can be calculated as follows: 
30 g H2 / 2.016 g/mol = 14.88 mol H2

The moles of nitrogen present in the mixture can be calculated as follows: 
10 g N2 / 28.01 g/mol = 0.3578 mol N2

According to the balanced equation, 3 moles of H2 reacts with 1 mole of N2 to form 2 moles of NH3. Thus, the moles of NH3 that can be formed from the given mixture are limited by the 0.3578 mol of N2 present. The theoretical yield of NH3 can be calculated as follows:

0.3578 mol N2 × (2 mol NH3 / 1 mol N2) × (17.031 g NH3 / 1 mol NH3) = 12.17 g NH3

Now, we can calculate the percent yield using the actual yield (8.4 g) and the theoretical yield (12.17 g):

Percent yield = actual yield / theoretical yield × 100% 
Percent yield = 8.4 g / 12.17 g × 100% 
Percent yield ≈ 69%

Therefore, the answer is B) 69%.

The Haber Process for the Production of Ammonia Is Represented