Percent Yield
• The amount of product calculated to form in a
reaction by doing a stoichiometry problem is called
the theoretical yield.
• This represents the maximum amount of product
that could form.
• Many times, however; the amount of product actually
obtained is less than predicted.
• The measured amount of product obtained from the
reaction is called the actual yield.
• Percent Yield is used to evaluate the efficiency of a
reaction.
Actual Yield
Percent Yield = ---------------------------- x 100
Theoretical Yield
Percent Yield
• Consider the reaction:
2 C (s) + 2 H2O (g)  CH4 (g) + CO2 (g)
a)How many grams of CH4 be produced from
225 g C?
b)If 120 g of CH4 was actually collected from the
reaction, then what was the percent yield for the
reaction?
•
Aluminum reacts the copper (II) sulfate according to
the reaction below. If 1.85 g Al reacts and the
percentage yield is 56.6%, what mass of Cu is
produced?
2 Al (s) + 3 CuSO4 (aq)  Al2(SO4)3 (aq) + 3 Cu (s)
Sample EOC Question
During the production of aspirin, 2.6 g of aspirin can
be formed from 2.0 g of salicylic acid. What is the
percent yield if only 1.7 g of aspirin is produced?
A. 35 %
B. 65%
C. 77%
D. 85%
Wrapping It Up
• Reflect on what you have learned concerning the today’s
topic.
• Respond to the following…
– What is the most important thing you learned today?
– What is one question you would still like answered?
– What is a way what you have learned today connects with
what you knew before?