Question

Ammonia is produced by the following reaction.


3H2(g) + N2(g) Right arrow. 2NH3(g)


When 7.00 g of hydrogen react with 70.0 g of nitrogen, hydrogen is considered the limiting reactant because
7.5 mol of hydrogen would be needed to consume the available nitrogen.
7.5 mol of nitrogen would be needed to consume the available hydrogen.
hydrogen would produce 7.5 mol more ammonia than nitrogen.
nitrogen would produce 7.5 mol more ammonia than hydrogen.

Answer 1

Answer: "7.5 mol of hydrogen would be needed to consume the available nitrogen."

Work:
- moles H2 = 7.00 g / 2.016 g·mol⁻¹ ≈ 3.47 mol
- moles N2 = 70.0 g / 28.02 g·mol⁻¹ ≈ 2.50 mol
- stoichiometry: 3 H2 per 1 N2, so H2 needed = 3 × 2.50 ≈ 7.50 mol

Because only ~3.47 mol H2 is available but ~7.50 mol is required to consume all the N2, hydrogen is the limiting reactant.