2 Eggs + 4 Bacon + 1 OJ + 2 Toast  1 Breakfast

Section 1: Defining Stoichiometry Chapter 8: Quantities in Chemical Reactions

Learning Goals 0 Describe the types of relationships indicated by a balanced chemical equation. 0 State the mole ratios from a balanced chemical equation.

Particle and Mole Relationships 0 Chemical reactions stop when one of the reactants is used up. 0 Stoichiometry is the study of quantitative relationships between the amounts of reactants used and amounts of products formed by a chemical reaction.

Particle and Mole Relationships 0 Using stoichiometry, we can: 0 Predict the amounts of products that form in a chemical reaction based on the amounts of reactants 0 Predict how much of the reactants are necessary to form a given amount of product

Particle and Mole Relationships 0 Predict how much one reactant is required to completely react with another reactant.

Example 0 Interpret the equation for the combustion of propane (C 3 H 8 ) in terms of representative particles, moles, and mass. C 3 H 8 + 5O 2  3CO 2 + 4H 2 O

Particle and Mole Relationships 0 A mole ratio is a ratio between the numbers of moles of any two substances in a balanced equation. 0 The number of mole ratios that can be written for any equation is (n)(n – 1) where n is the number of species in the chemical reaction.

Practice 0 Determine all possible mole ratios for the following chemical equations. Balance the equations if needed.

Practice 0 Al(s) + O 2 (g)  Al 2 O 3 (s)

Practice 0 Fe(s) + H 2 O (l)  Fe 3 O 4 (s) + H 2 (g)