12.3 Limiting Reactant and Percent Yield
12.3 Limiting Reactant and Percent Yield
Lesson Objectives
- Analyze a chemical reaction in order to determine which reactant is the limiting reactant and which is the
excess reactant. - Calculate the amount of excess reactant remaining after a reaction is complete.
- Calculate the theoretical yield of a reaction when the available amounts of each reactant are known.
- Calculate the percent yield of a reaction based on the theoretical and actual yields.
Lesson Vocabulary
- actual yield
- excess reactant (reagent)
- limiting reactant (reagent)
- percent yield
- theoretical yield
Check Your Understanding
Recalling Prior Knowledge
- What is the relationship between the amounts of reactants in a chemical reaction that follows ideal stoichiom-
etry? - How is the mass of a product determined when the mass of one reactant is known?
We have seen that the reactants in a chemical reaction combine with one another in a specific molar ratio that is
described by the balanced equation. What if a reaction is performed in which the reactants are not present in that
exact ratio? In this lesson, you will learn about this type of reaction and how to calculate the amounts of products
that are expected to be formed.
Identifying the Limiting Reactant
Everyday Limiting Reactant
Cooking is a great example of everyday chemistry. In order to correctly follow a recipe, a cook needs to make sure
that he has plenty of all the necessary ingredients in order to make his dish. Let us suppose that you are planning on
making some pancakes for a large group of people (Figure12.8).