1. Using moles to figure out chemical equations Pt + 4 HNO 3 + 6 HCl → H 2 PtCl 6 + 4 NO 2 + 4 H 2 O

2. What difference does it make how many moles there are? Pt + 4 HNO 3 + 6 HCl → H 2 PtCl 6 + 4 NO 2 + 4 H 2 O The price of platinum is $47/g The price of HNO 3 is $0.47/g Would it be wise to ignore mole ratios?

3. Multiply that to the industrial scale 1 tonne of Pt = 47 million dollars

4. Stoichiometry: measuring the elements Stoichiometry – calculating the relative amounts of reactants and products in chemical reactions

5. Mole ratio Mole ratio – the ratio of the amount in moles, of reactants and products in a chemical reaction :

6. How to find a mole ratio 1. Start with a balanced equation N 2 (g) + 3H 2 (g) → 2NH 3 (g) 2. Find the ratio of the coefficients 1 molecule N 2 (g): 3 molecules H 2 (g): 2 molecules NH 3 (g) 3. Convert molecules to moles 1 mole N 2 (g): 3 moles H 2 (g): 2 moles NH 3 (g) [mole ratio] Can write as 1:3:2

7. Review Question: How many molecules in a dozen molecules? 12 How many molecules in a mole of molecules? 6.02x10 23

8. What’s the mole ratio? A + 4 B + 6 C → 3 D 1:4:6:3

9. Let’s balance an equation H 2 (g) + O 2 (g) → H 2 O(l)

10. Crossing the mole bridge: how to do mole calculations in 3 easy steps!!!

11. 1. Find the balanced equation 2. Identify the knowns and unknowns 3. Cross the mole bridge – Only moles are allowed on the mole bridge – To cross, multiply or divide

12. Problem: If you burn 15 g of propane, C 3 H 8 (g) (the gas in barbecues), how much oxygen was needed? (hint burning hydrocarbons produces carbon dioxide and water) C 3 H 8 (g) + 5O 2 (g) → 3CO 2 (g) + 4H 2 O(l)

15. 2H 2 (g) + O 2 (g) → 2H 2 O(l) 2 g x g