1. Limiting reactants

2. The limiting reactant is the reactant that runs out first or the one that produces the least amount of products
Common sense example. John buys 8 hotdogs. How many products can he make if he has an unlimited supply of buns? Jill buys 10 buns. How many products can she make if she has an unlimited supply of hotdogs?
Hotdog + bun  yummy
What is the maximum number of yummies could you make with 8 hotdogs and 10 buns?
Why? Were limited by the number of hotdogs;therefore, the hotdogs were the limiting reactant.
8 yummies

3. Zn (s) + HCl (aq)  H2 (g) + ZnCl2 (aq) 2
If 25.0 grams of zinc was reacted with 25.0 grams of hydrochloric acid(36.46), how many grams of hydrogen gas could be produced? What is the limiting reactant?
Zinc + hydrochloric acid  hydrogen + zinc chloride
Zn (s) + HCl (aq)  H2 (g) + ZnCl2 (aq) 2
25.0 g
25.0 g
? g
Really 2 separate stoich problems.
0.771 g H2
Which one is smaller?
0.691 g H2
HCl is the L.R. because it produces the least amount of product.