Ch. 9 StoichiometryStoichiometry is a branch of chemistry

that deals with the mass relationships of elements in compounds and the mass relationships between reactants and products in chemical reactions.

2 Types of Stoichiometry1. Composition Stoichiometry – is the

mass relationships of elements in chemical compounds.Ex. Molar mass of Li is 6.941 grams

2. Reaction Stoichiometry – is the mass relationship among reactants and products of a chemical reaction.Ex. NaCl + H2O HCl + NaOH 58.44g 18.02g 36.46g 40.00g

4 Reaction – Stoichiometry Problems1. Mole to Mole2. Mass to Mass3. Mole to Mass4. Mass to Mole

EXAMPLES ???Sample Problems 9.1 – 9.5Limiting Reactant is the reactant that

limits the amount of the other reactants that can combine, and the amount of products formed in a chemical reaction.

Excess Reactant is the substance that is not used up completely in a reaction.Ex. If a bus holds 50 people and 60 are

waiting to ride the bus, 10 will be left in excess.

Sample problems 9.6 – 9.7

Percent Yield is the ratio of the actual yield to theoretical yield times 100%.(Actual yield / Theoretical yield) X

100%Theoretical yield is the maximum amount

of product that can be produced from a given amount of reactant.

Actual yield is the measured amount of a product obtained from the product of a reaction.

Sample Problem 9.8