# Laboratory 08 LIMITING REACTANT LAB.

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Laboratory 08 LIMITING REACTANT LAB

Objectives Understand mole-to-mole ratio in a balanced chemical reaction Identify the limiting and excess reactant in a chemical reaction based on experimental observation Conduct limiting reactant calculations to predict theoretical yield

Limiting Reagent: The reagent that is completely used up in a chemical reaction. Excess Reagent: Reagent not completely used up in a chemical reaction.

The Concept of Limiting Reactants
Stoichiometric mixture N2(g) + 3H2(g)  2NH3(g)

Limiting reactant mixture
N2(g) + 3H2(g)  2NH3(g)

Calculations Involving a Limiting Reactant

Example: Find the limiting reagent when 1. 22g O2 reacts with 1
Example: Find the limiting reagent when 1.22g O2 reacts with 1.05g H2 to produce H2O.

Example: Find the limiting reagent when 1. 22g O2 reacts with 1
Example: Find the limiting reagent when 1.22g O2 reacts with 1.05g H2 to produce H2O. 2H2 (g) + O2 (g)  2H2O (l) Convert mass to moles: 0.038 mol O2, mol H2 Calculate H2 moles necessary to react with O2: mol H2. Compare mol H2 to actual mol of H2 (0.5mol H2), Since 0.5 mol H2 is more than mol H2, H2 is the excess reagent and O2 is the limiting reagent.