2. Can’t directly measure moles Measure units related to moles: –Mass (molar mass) –Number of particles (6.02 x 10 23 ) –Liters of gas (22.4 Liters at STP) Can determine relationships between chemicals in a reaction using any units with stoichiometry

3. Write a balanced chemical equation Convert given substance “A” into moles To Convert moles of substance “A” into moles of substance B Use Mole to Mole Ratio Convert Moles of Substance “B” into desired units

5. Calculate the number of grams of NH 3 produced by the reaction of 5.40 g of hydrogen with an excess of Nitrogen. Balance the equation: N 2 + 3H 2  2NH 3

6. Known: 5.40 g H 2 Unknown: g NH 3 5.40 g H 2 Given Quantity 2.02 g H 2 1 mol H 2 Change given unit into moles 3 mol H 2 2 mol NH 3 Mole Ratio 1 mol NH 3 17.04 g NH 3 Change moles into desired units

7. Calculate the number of moles of ethane (C 2 H 6 ) needed to produce 12.6 g of water using the following equation: 2 C 2 H 6 + 7 O 2  4 CO 2 + 6 H 2 0 12.6 g H 2 O 1 mol H 2 O 2 mol C 2 H 6 18.02 g H 2 O 6 mol H 2 0 = 0.233 mol C 2 H 6

8. How many molecules of oxygen are produced when 29.2 g of water is decomposed by electrolysis? 2H 2 0  2H 2 + O 2 29.2 g H 2 O 18.02 g H 2 01 mol O 2 1 mol H 2 O 1 mol O 2 2 mol H 2 O 6.02 x 10 23 molec O 2