Chapter 12: Stoichiometry WASILLLA HIGH SCHOOL

Balanced Chemical Equations  A balanced chemical equation provides the same kind of quantitative information that a recipe does.

Using Everyday Equations  An equation can represent the manufacturing of a single tricycle. 12.1

How do chemists use balanced chemical equations?  Chemists use balanced chemical equations as a basis to calculate how much reactant is needed or product is formed in a reaction.  The calculation of quantities in chemical reactions is a subject of chemistry called stoichiometry.

Writing and Using Mole Ratios  Mole-Mole Calculations  A mole ratio is a conversion factor derived from the coefficients of a balanced chemical equation interpreted in terms of moles. 12.2

Solution Diagram 12.2

Moles to Moles – 1 step problem

Converting from moles to moles

Converting from grams to moles  2 step problems

Converting moles to grams How many moles of aluminum oxide would be produced from 85.0 grams of Aluminum?

Converting from grams to grams

Limiting Reagent  In a chemical reaction, you will always run out of one of the reactants first.  Whatever reactant you run out of first is the Limiting Reagent because it limits how much product you can make

Sample Problem:

% Yield  The percent yield is a measure of the efficiency of a reaction carried out in the laboratory.  The theoretical yield is the maximum amount of product that could be formed from given amounts of reactants.  In contrast, the amount of product that actually forms when the reaction is carried out in the laboratory is called the actual yield.