A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H₂ + N₂ $\rightleftharpoons$ 2NH₃
An analysis of the mixture at equilibrium revealed 2.1 mol N₂, 2.8 mol H₂, and 1.8 mol NH₃. How many moles of H₂ were present at the beginning of the reaction?

Question

A mixture of nitrogen and hydrogen was allowed to come to equilibrium at a given temperature. 3H₂ + N₂

\rightleftharpoons

2NH₃
An analysis of the mixture at equilibrium revealed 2.1 mol N₂, 2.8 mol H₂, and 1.8 mol NH₃. How many moles of H₂ were present at the beginning of the reaction?

Quizplus · Accepted Answer

To find the initial moles of H2, use the stoichiometry of the reaction. At equilibrium, 1.8 mol NH3 means 0.9 mol N2 and 2.7 mol H2 were consumed. Initial H2 = 2.8 mol (equilibrium) + 2.7 mol (consumed) = 5.5 mol.

A Mixture of Nitrogen and Hydrogen Was Allowed to Come ⇌\rightleftharpoons⇌

A Mixture of Nitrogen and Hydrogen Was Allowed to Come $\rightleftharpoons$