Which concept is used for calculating the amounts of reactants and products in a chemical reaction?

• A. Stoichiometry
• B. Limiting reagent
• C. Percent yield
• D. Ideal Gas Law

Answer: (A)

Stoichiometry is the calculation of quantities in a chemical reaction using the balanced equation. By reading the coefficients, you establish mole ratios that link reactants and products, allowing you to convert a known amount of one substance into the amount of another, determine how much of a reactant is needed, or predict the theoretical yield of product. This is exactly what’s being asked—figuring out how much of each substance is involved or produced from the reaction.

Limiting reagent is a related concept that comes into play when reactants are present in finite amounts, but the calculation method itself is stoichiometry. Percent yield compares the actual amount obtained to the theoretical yield after the reaction, so it’s about efficiency rather than performing the quantity-to-quantity calculations. The Ideal Gas Law deals with gases and relates pressure, volume, temperature, and moles, which isn’t the general tool for determining amounts from a balanced reaction.