PERCENT YIELD

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

 

~ 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 ___ Al2O3 + ___ CO2 + ___ H2O

 

ANSWER:
_2_ Al(HCO3)3
___ 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 ___ H2O

 

 

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