Practice Questions

Stoichiometric mixture. P₄O₁₀ = 0.5 mol. Mass = 142 g.

Fe = 0.5 mol (limiting). FeS formed = 0.5 mol. Mass = 44 g.

Both react stoichiometrically. CO₂ formed = 0.5 mol. Volume = 11.2 dm³.

Al = 0.667 mol and is limiting. H₂ produced = 1 mol. Volume = 22.4 dm³.

An inexpensive reactant is often used in excess so that the valuable reactant is completely consumed.

AgNO₃ = 0.2 mol and Cu = 0.1 mol. Stoichiometric mixture. Ag formed = 0.2 mol = 21.6 g.

2 mol butane require 13 mol O₂, exactly the amount available.

N₂ = 0.5 mol. H₂ required = 1.5 mol but available = 4 mol. Excess H₂ = 2.5 mol = 5 g.

ZnS ≈ 1 mol and O₂ = 1.5 mol. Stoichiometric mixture. ZnO = 1 mol = 81 g.

An excess reactant is supplied in greater quantity than required and remains after the reaction.