1. Stoichiometry
Chapter 12

2. A balanced chemical equation provides the same kind of quantitative information that a recipe does.
Everyday Equations

3. Using balanced chemical equations
Chemists use balanced chemical
equations to calculate how much
reactant is needed or product is
formed in a reaction.
Stoichiometry: the calculation of quantities in chemical reactions
Using balanced chemical equations

4. Mass and atoms are conserved in every chemical reaction.
Conservation of Mass

5. A mole ratio is a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles.
N2(g) + 3H2(g)  2NH3(g)
1 mole N2 2 mole NH3 3 mole H2
3 mole H2 1 mole N2 2 mole NH3
Mole Ratio

6. In a chemical reaction, an insufficient quantity of any of the reactants will limit the amount of product that forms.
Limiting reagent: reagent that determines the amount of product that can be formed by the reaction. The reaction occurs only until the limiting reagent is used up.
Excess reagent: the reactant that is not completely used up in a reaction.
Limiting Reagents

7. Theoretical yield: max amount of product that COULD be formed from given amounts of reactants
Actual yield: amount of product ACTUALLY formed in lab
Percent yield: ratio of actual yield to theoretical yield, as percent. Measure of efficiency of reaction during procedure.
Percent Yield