PERCENT YIELD

~ compares the actual amount of product that you made (in an experiment) to the amount of

~ ACTUAL YIELD:  amount of product that you made in an experiment

~ THEORETICAL YIELD:  amount of product that you should have made (according to
calculations)

~          % YIELD =      ACTUAL YIELD      X 100

THEORETICAL YIELD

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EXAMPLE
What is the percent yield if a student makes 5.2 grams of carbon dioxide by decomposing 9.5 grams of aluminum bicarbonate?

___ Al(HCO3)3  à  ___ Al2O3  +  ___ CO2  +  ___ H2O

_2_ Al(HCO3)3
à  ___ Al2O3  +  _6_ CO2  +  _3_ H2O

9.5 g                                   ? g

* I am given the actual yield in the problem;  I need to find the theoretical yield. *

9.5 g Al(HCO3)3 | 1 mole Al(HCO3)3 |     6 moles CO2     |   44 g CO2    = 6.0 g CO2
|  210 grams         | 2 moles Al(HCO3)3 | 1 mole CO2

So, 6.0 g is the theoretical yield.

% yield =  5.2 g  x 100 = 87 %
6.0 g

PRACTICE PROBLEM

What is the percent yield if a student produces 3.7 grams of water by reacting 7.5 grams of oxygen with excess hydrogen?

___ H2  +  ___ O2  à  ___ H2O