The number of bicycles that can be assembled is limited by whichever part runs out first. In the inventory shown in this figure, wheels are that part. The reactant that is completely consumed by the reaction Limiting Reagent

Stoichiometric mixture – N 2 (g) + 3H 2 (g)  2NH 3 (g)

Limiting reactant mixture –N 2 (g) + 3H 2 (g)  2NH 3 (g)

–Limiting reactant is the reactant that runs out first –When the limiting reactant is exhausted, then the reaction stops –Excess reactant is the reactant that is not exhausted in the reaction For a Limiting reactant mixture the number of moles are not balanced to match the reaction equation – N 2 (g) + 3H 2 (g)  2NH 3 (g)

Limiting reagent – The reactant whose number of moles divided by its stoichiometric coefficient is the smallest. See pages in your textbook.

% yield- measures the efficiency of reaction – Normally can’t be larger than 100% – Most are less than 100 % b/c: Reactions don’t go to completion Impure reactants Competing side reaction Loss of product during transfer or filtration

Actual yield- amt. of product formed in lab Theoretical yield- amt. product that could be formed from calculations % Yield: actual yield X 100 theoretical yield

CaCO 3 (s)  CaO (s) + CO 2 (g) – What is the theoretical yield of CaO if 24.8 g CaCO 3 is heated? – What is the % yield if 13.1 g CaO is produced? 24.8 g CaCO g CaCO 3 1 mol CaCO 3 1 mol CaO = gCaO 13.9 gCaO 13.1 g CaO x 100 =94% actual theoretical =