1. Calculate the mass of Cu produced? Mass of beaker and Cu – mass of beaker

2. Calculating percent yield Percent yield – a way to compare how much you “should” get to how much you actually got Percent Yield = Actual yield Theoretic yield X 100

3. 1. Unit 2 Test grade = 2. Unit 2 Test Average = 81% 3. How did you prepare for the test? 4. How will you prepare for the next test? 5. Set a goal. Day 1 10-17 period 3 If you met your goal you must improve by at least 1 percentage point. If you did not, your goal stays the same.

4. 1. Unit 2 Test grade = 2. Unit 2 Test Average = 81% 3. How did you prepare for the test? 4. How will you prepare for the next test? 5. Set a goal. Day 2 10-20 period 1 If you met your goal you must improve by at least 1 percentage point. If you did not, your goal stays the same.

5. 2Al (s) + 3CuCl 2(aq)  2AlCl 3(aq) + 3Cu (s) According to the reaction above if you start with about 27 grams of aluminum how much copper should you produce (in grams)? What is this calculation called?

6. Stoichiometry Reaction Stoichiometry – relates quantities of reactants and products in chemical reactions Mole ratio – conversion factor that relates the amounts in moles of any two substances involved in a chemical rxn Example: 4NH 3 (g) + 6NO(g) 5N 2 (g) + 6H 2 O(l)

7. Stoichiometry Mole ratio – just another player in the conversion game - Used to change from one substance to another - Does NOT change units - Does change substance

8. Converting: Mass to moles Moles to mass Moles to atoms / molecules / particles Atoms / molecules / partilces to moles Moles to liters Liters to moles Changing a substance = = Molar mass Avogadro’s number = Avogadro’s law =Mole ratio

9. Stoichiometry Mole ratio – just another player in the conversion game Mole ratios are exact – do not limit sig. figs.

10. Stoichiometry 4NH 3(g) + 6NO (g) 5N 2(g) + 6H 2 O (l) Start with 20 mols NH 3 mols N 2 Start with 20 grams NH 3 moles NO Start with 20 grams NO grams N 2 __?__

11. In your own words: 1. Define mole ratio (What is it? How is it determined?) Day 2 10-20 period 3

12. Stoichiometry Start with 20 mols NH 3 molecules N 2 Start with 20 grams NH 3 molecules NO __?__ 4NH 3(g) + 6NO (g) 5N 2(g) + 6H 2 O (l) 1.5e25 molecules N 2 1.1e24 molecules NO

13. STEPS FOR SOLVING: 1. Identify the Balanced chemical equation 2. Identify what you know and what you need to know 3. Get an idea of what you need to do 4. Start your conversion

14. If you produce 116 grams of sodium chloride by reacting sodium and chlorine how many mols of sodium must you have used? 2Na + Cl 2 → 2NaCl 116 g NaCl = ____ mols Na answer = 2 mols Na Stoichiometry

15. Cupric chloride decomposes and 127 grams of solid copper form. How many liters of chlorine gas are produced at STP? CuCl 2 → Cu + Cl 2 127 g Cu = ____ liters Cl 2 answer = 44.8 liters Cl 2 Stoichiometry

16. Limiting Reactant – the reactant that limits the amounts of the other reactants that can combine and the amount of product that can form in a chemical reaction – the one you will run out of Excess Reactant – any substance that is not used up completely in a reaction – left over Limiting Reactants