1. Review Mg + 2 HCl  MgCl 2 + H 2 How many Liters of H 2 would be produced with 56 g Mg?

2. Limiting Reactants & Percent Yield Chapter 9, Section 2

3. Limiting Reactants o Limiting reactant (LR): the reactant that controls the quantity of product. o Once you run out of it, you can’t make any more product!! o Excess reactant: the reactant(s) that is left over

4. Limiting Reagent (with grilled cheese) 1 Cheese slice + 2 pieces of bread → 1 Grilled Cheese + → 9 slices of cheese 12 pieces of bread How many grilled cheese sandwiches (product) can you make? Limiting Reagent: Excess Reagent:

5. How do we calculate using stoich?? Calculate the quantity of product each reactant gives you ▫The reactant that gives you the lowest, is the LR.

6. Mg + 2 HCl  MgCl 2 + H 2 If you combine 35.5 grams of magnesium with 28.1 grams of hydrochloric acid. a.What is the limiting reagent? b.How many grams of MgCl 2 is produced?

7. Example: 2Cu (s) + S (s)  Cu 2 S (s) a. What is the limiting reagent when 80.0g of Cu reacts with 25.0g of S? b. How many grams of Cu 2 S can be formed?

8. Zn + 2HCl  ZnCl 2 + H 2 1. What is the limiting reagent if 15.5 grams of zinc are combined with 26.3 grams of HCl? 2. how many liters of H 2 are produced?

9. Theoretical yield: The maximum amount of product obtained in a chemical reaction (this is the calculated amount!) Actual Yield: the amount of product when the reaction is carried out in the laboratory (often less than the theoretical yield)

10. Where Do products Get Lost? Products lost ▫Side reactions ▫Purification techniques ▫Gases hard to collect

11. The ratio of the actual yield to the theoretical yield expressed as a percent % Yield = actual yield x 100 theoretical yield (stoich) Percent yield

12. CaCO 3(s)  CaO (s) + CO 2(g) a. What is the theoretical yield of CaO if 24.8g of CaCO 3 is heated? b. What is the percent yield if 13.1g CaO is produced?