Chemical Calculations Lesson # 5 - Stoichiometry

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: N2 + H2 → NH3 (the balanced equation) mol : mol : mol (the mole ratio)

Example 2 Determine how many moles of oxygen are produced when 3.5 moles of water decompose. H2O → H2 + O2

Example 3 Determine how many moles of phosphorus are needed to form 4.5 moles of diphosphorus pentoxide. P + O2 → P2O5

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

Example 5 Calculate the mass of hydrogen needed to produce 15.5 g of ammonia in the presence of an abundant amount of nitrogen. N2 + H2 → NH3