1. LIMITING REAGENT (LR) gets completely used up in the reaction
limits the amount of product that can be formed

2. EXCESS REAGENT more than enough to react with the limiting reagent
left over in the chemical reaction

3. CALCULATIONS
O H2 → 2 H2O
1.When 6.7 moles of O2 react with 3.2 moles of H2, which reactant is limiting – oxygen or hydrogen – and why?

4. CALCULATIONS O2 + 2 H2 → 2 H2O 2. How many moles H2O are formed?
start with the LR
LR limits the amt of product formed

5. CALCULATIONS
O H2 → 2 H2O
3. How many grams of the excess reactant remain unreacted?
start with the LR and calc. amt of excess reactant used up
subtract what is used up from the original amount of excess reagent

6. CALCULATIONS
O H2 → 2 H2O