Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The limiting reagent in a chemical reaction is the reactant that gets completely used up first and thus limits how much product can be formed.
Related terms
Excess Reagent: This is any reactant that remains after a chemical reaction has reached completion. In our cookie analogy, this would be any extra flour left over after all eggs have been used up.
Stoichiometry: This branch of chemistry deals with quantitative relationships between reactants and products in a chemical reaction - like figuring out which ingredient will run out first when baking cookies!
Yield: Yield refers to how much product was actually produced when carrying out a reaction.