1. 9.3 NOTES Stoichiometry Non- Mass – Mass Problems

2. B. Non-mass-mass calculations
These problems involve moles and/or grams in some combination. These problems have fewer fractions than the normal mass-mass problems.

3. a. Example: If 12.8 grams of lithium are reacted with oxygen gas, how many moles of lithium oxide are formed?
4Li + O2  2Li2O
Given: 12.8g Li (6.94g/mol) Find: moles Li2O
12.8 g Li x 1 mol Li x 2 mol Li2O
6.94 g Li 4 mol Li = mol Li2O

4. b. If 0.45 mole of water is decomposed, how many moles of oxygen gas are produced?
2H2O  2H2 + O2
Given: 0.45 mol H2O Find: moles O2
0.45 mol H2O x 1 mol O2
2 mol H2O = mol O2