Practice question
Question
How many grams of Fe are required to produce 8.96 L of H₂ at STP with excess HCl? (Atomic mass: Fe = 56)
Explanation
Reaction: Fe + 2HCl → FeCl₂ + H₂. Moles of H₂ = 8.96/22.4 = 0.4 mol. 1 mol H₂ from 1 mol Fe; mass = 0.4 × 56 = 22.4 g.