Question

the reaction between water and ammonia to produce nitrogen dioxide and hydrogen gas requires 216 kj per mole of ammonia reacted. Determine the mass of hydrogen produced in a reaction that consumes 685kj.

Answer 1

22.4 g

Step-by-step explanation:

We know we will need a balanced equation with molar masses, so let’s gather all the information in one place.

M_r: 2.016

4H₂O + 2NH₃ ⟶ 2NO₂ + 7H₂; ΔH = 216 kJ/mol NH₃

1. Calculate the moles of NH₃

216 kJ ≡ 1 mol NH₃

Moles NH₃ = 685 × 1/216

Moles NH₃ = 3.171 mol NH₃

2. Calculate the moles of H₂

The molar ratio is 7 mol H₂:2 mol NH₃

Moles of H₂ = 3.171 × 7/2

Moles of H₂ = 11.10 mol H₂

3. Calculate the mass of H₂

Mass of H₂ = 11.10 × 2.016

Mass of H₂ = 22.4 g