1. Chemical Calculations
Lesson # 5 - Stoichiometry

2. Stoichiometry
Stoichiometry is the procedure for calculating quantities of reactants and products in chemical reactions using mole ratios. A mole ratio is the ratio of moles in a balanced chemical equation.
Example 1: N H2 → NH3 (the balanced equation)
mol : mol : mol (the mole ratio)

3. Example 2
Determine how many moles of oxygen are produced when 3.5 moles of water decompose.
H2O → H O2

4. Example 3
Determine how many moles of phosphorus are needed to form 4.5 moles of diphosphorus pentoxide.
P O → P2O5

5. Example 4
How many moles of oxygen are required to react with 9.7 g of magnesium to produce magnesium oxide?
Mg O2 → MgO

6. Example 5
Calculate the mass of hydrogen needed to produce 15.5 g of ammonia in the presence of an abundant amount of nitrogen.
N H2 → NH3