Stoichiometry
Science

Any reactant that remains after a chemical reaction is over
Excess reactant
Any reactant that remains after a chemical reaction is over. Excess reactant. The excess reactant is the substance that is left over when a reaction has finished because there was more of it than needed to completely react with the other substances.

A reactant that is used up first in a reaction; it determines the amount of product formed
Limiting reactant
A reactant that is used up first in a reaction it determines the amount of product formed. Limiting reactant. The limiting reactant is the substance in a chemical reaction that runs out first, stopping the reaction and determining how much product is made.

The ratio between the number of moles of any two substances in a balanced equation
Mole ratio
The ratio between the number of moles of any two substances in a balanced equation is called the mole ratio. In simple terms, a mole ratio tells you how many units of one substance react or are produced with units of another in a chemical reaction.

The actual yield expressed as a percentage of the theoretical yield
Percent yield
The actual yield expressed as a percentage of the theoretical yield. Percent yield. In Science, percent yield shows how efficient a chemical reaction is by comparing the actual amount of product to the maximum possible amount.

The maximum amount of product that can be produced from a set amount of reactant
Theoretical yield
The maximum amount of product that can be produced from a set amount of reactant is called the theoretical yield. Theoretical yield is the calculated amount of product expected from a chemical reaction based on the reactants used, assuming everything goes perfectly.