1. What percent is 8 of 20?
If a reaction made 50. g of product, but was supposed to produce 75. g, what was the percent produced? 8 20
x 100 =
40%
50.
75.
x 100 =
67%
Percent Yield:
amount of product recovered as a percent of product intended.

2. theoretical yield:
the maximum amount of product that could be formed from limiting reactant. (calculated yield)
actual yield:
the amount of product actually recovered in the laboratory.

3. Calcium carbonate, found in seashells, decomposes by heating as shown in the reaction.
What is the theoretical yield, in grams, of CaO if 24.8 g CaCO3 is decomposed?
1 mol CaCO3
g CaCO3
1 mol CaO
1 mol CaCO3
g CaO
1 mol CaO
24.8 g CaCO3 x x x =
13.9 g CaO

4. Calcium carbonate, found in seashells, decomposes by heating as shown in the reaction.
What is the percent yield if 13.1 g CaO is actually produced when 24.8 g CaCO3 is decomposed?
1 mol CaCO3
g CaCO3
1 mol CaO
1 mol CaCO3
g CaO
1 mol CaO
24.8 g CaCO3 x x x
theoretical yield =
13.9 g CaO
13.1 g CaO
“theoretical yield”
x 100% =
94.3 %

5. WHY? % yield is usually LESS than 100%
13.1 g CaO
“theoretical yield”
x 100% =
94.3 %
% yield is usually LESS than 100%
WHY?
Could it ever be MORE than 100%?

6. Quick Quiz!
1. The theoretical yield is also called the…
percent yield
actual yield
calculated yield
experimental yield

7. theoretical yield = 15.4 g CO2
actual yield
Quick Quiz.
2. What is the percent yield of CO2 if g of CO2 are recovered when g of C8H18 are combusted?
2 C8H O2  16 CO H2O
106%
94.7%
34.2%
62.5%
act.
theo.
x 100
14.6 g CO2
15.4 g CO2
x 100% = ?
theoretical yield = g CO2
1 mol C8H18
g C8H18
16 mol CO2
2 mol C8H18
44.01 g CO2
1 mol CO2
5.00 g C8H18 x x x =