Ch. 9.4: Percent Yield

1
Ch. 9.4 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.

2

• Percent Yield is used to evaluate the efficiency
  of a reaction.
• Actual
  Yield
• Percent Yield ----------------------------
  x 100
• Theoretical Yield
• Real life example You made 2 dozen cookies, but
  your dog jumped up on the counter and ate 7 of
  them. What was your percent yield?

3
Percent Yield

• Consider the reaction
• 2 C (s) 2 H2O (g) ? CH4 (g) CO2
  (g)
• How many grams of CH4 be produced from
  225 g C?
• If 120 g of CH4 was actually collected from the
  reaction, then what was the percent yield for the
  reaction?

4

• 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)
• PA/T

5
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?
• 35 C. 77
• 65 D. 85

6
Wrapping It Up

• Reflect on what you have learned concerning the
  todays 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?