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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.
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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)
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 1.05g H2 to produce H2O. 2H2 (g) + O2 (g) 2H2O (l) • Convert mass to moles: 0.038 mol O2, 0.5 mol H2 • Calculate H2 moles necessary to react with O2:0.076 mol H2. • Compare 0.076 mol H2to actual mol of H2 (0.5mol H2), • Since 0.5 mol H2 is more than 0.076 mol H2, H2 is the excess reagent and O2 is the limiting reagent.