Do these problems on a separate sheet of paper. Circle final answer and show all of
your work.
Theoretical yield and percentage yield
1. The reaction that’s used to make refrigerant, Freon-12, CCl2F2, is described
as:
CCl4 + SbF3  CCl2F2 + SbCl3
In a certain experiment, 14.6 g of SbF3 was allowed to react with an excess of
CCl4. After the reaction was finished, 8.62 g of CCl2F2 was isolated from the
reaction mixture.
a. What was the theoretical yield of CCl2F2 in grams?
b. What was the actual yield of CCl2F2 in grams?
c. What is the percent yield of CCl2F2 in grams?
2. The combustion of methyl alcohol, CH3OH, in a plentiful supply of oxygen
follows the equation
CH3OH + O2  CO2 + H2O
When 6.40 g CH3OH was mixed with only a slight excess of oxygen and
allowed to react, 6.12 g of CO2 was obtained.
a. Based on the equation above, what was the theoretical yield (in
grams) of CO2 in this experiment?
b. What was the actual yield of CO2 in grams?
c. What was the percent yield of CO2?
Limiting reactant problems
1. Aluminum reacts with sulfuric acid (H2SO4), which is the acid in car batteries
and produces aluminum sulfate and hydrogen gas. If 20.0 g of aluminum is
put into a solution containing 115 g of H2SO4,
a. Which reactant is limiting?
b. How many moles of hydrogen gas are formed?
c. What mass of aluminum sulfate is produced?
d. How many grams of the excess reactant are left over?
2. Under appropriate conditions, acetylene (C2H2) and HCl react to form vinyl
chloride, C2H3Cl. This substance is used to manufacture polyvinyl chloride
(PVC) plastics and has been shown to be carcinogenic. The equation for the
reaction is:
C2H2 + HCl  C2H3Cl
In a given instance, 35.0 g of C2H2 is mixed with 51.0 g of HCl.
a. What is the limiting reactant?
b. How many grams of C2H3Cl are formed?
c. How many grams of the reactant in excess are left over after the reaction
is complete?
3. Choloflourocarbons, commonly known as Freon (CFC’s), have been
implicated in the gradual destruction of the Earth’s ozone shield. One of
these, Freon-12, is a gas that is used as a refrigerant and is prepared by the
reaction:
CCl4 + SbF3  CCl2F2 + SbCl3
If 150 g of CCl4 is mixed with 100 g SbF3,
a. How many grams of CCl2F2 can be formed?
b. How many grams of which reactant will remain after the reaction has
ceased?