Yield in chemistry refers to the amount of product obtained in a chemical reaction. It is a measure of the efficiency of a chemical reaction and is expressed as a ratio of moles of product to moles of reactant. Yield is one of the primary factors that scientists must consider in organic and inorganic chemical synthesis processes).

There are different types of yield in chemistry, including:

• Actual Yield: The amount of product obtained in a chemical reaction under specific conditions/04%3A_Stoichiometry_of_Chemical_Reactions/4.4%3A_Reaction_Yields).
• Theoretical Yield: The amount of product that may be produced by a reaction under specified conditions, as calculated per the stoichiometry of an appropriate balanced chemical equation/04%3A_Stoichiometry_of_Chemical_Reactions/4.4%3A_Reaction_Yields).
• Percent Yield: The extent to which a reactions theoretical yield is achieved, expressed as a percentage/04%3A_Stoichiometry_of_Chemical_Reactions/4.4%3A_Reaction_Yields). It is calculated by dividing the actual yield by the theoretical yield and multiplying by 100% .

In chemical reaction engineering, "yield", "conversion" and "selectivity" are terms used to describe ratios of how much of a reactant was consumed (conversion), how much desired product was formed (yield) in relation to the undesired product (selectivity), represented as X, Y, and S).

Yield is an important concept in chemistry because it helps chemists determine the efficiency of a reaction and make adjustments to improve the yield.