1. Warm-Up
What happens if you don’t have enough of one of your reactants?

2. Limiting Reactants

3. Vocabulary
Limiting Reactant – the reactant that you run out of first in a chemical reaction
Reactant in Excess – the reactant that you will have left over after all of the limiting reactant is consumed

4. Practice Problem
Identify the limiting reactant and the mass of water produced when g of hydrogen gas reacts with g of oxygen gas at STP.

5. Step 1
Determine how many moles of the product can be produced from each given amount of reactant.

6. Step 2
Determine which reactant will produce the fewest moles of product. This is your limiting reactant, and therefore gives you the amount of product you can form.

7. Step 3
Convert the moles of product that will be produced to the units that the problem asks you for if you need to (in this case mass). This is a one-step conversion problem using your islands.

8. Practice
What mass of barium nitride is produced from the reaction between 22.6 g of barium and 4.2 g of nitrogen gas? What is you limiting reactant?

9. Percent Yield Expected Yield – amount of product that should be formed
Actual Yield – amount of product that actually forms

10. Practice
Determine the percent yield for the reaction above if only 21.5 g of barium nitride was actually collected.

11. Warm-Up Have your pre-lab out on your desk!
Calculate the mass of sodium bromide formed when 50.2 g of nitrogen tribromide reacts with 57.5 g of sodium hydroxide.
Unbalanced Reaction: (balance this first!)
NBr3 + NaOH  N2 + NaBr + HBrO

12. Pre-Lab #1
Baking Soda: NaHCO3 Vinegar: HC2H3O2

13. Pre-Lab #2
NaHCO3 (s) + HC2H3O2 (aq)  NaC2H3O2 (aq) + CO2 (g) + H2O (l)

14. Pre-Lab #3
NaHCO3 : g HC2H3O2 : g NaC2H3O2 : g

15. Limiting Reactants Lab
Change to 65 mL of Vinegar!
Erlenmeyer flask
Graduated cylinder
Swirl gently (2 minutes)
Hot plates
Balances