A solution of hydrochloric acid contains 5.22 g of HCl. When it is allowed to react with 3.25 g of solid K₂CO₃, the products are KCl, CO₂, and H₂O. Which reactant is in excess?

Strategy As for any reaction stoichiometry problem, we should start with a balanced equation. One way to proceed from there is to calculate the amount of one reactant that would combine with the given amount of the second reactant. Comparing that with the amount actually available will reveal the limiting reactant.