Section 1: Balancing Equations and Simple
Stoichiometry
Balance the following equations:
1)
___ N2 + ___ F2  ___ NF3
2)
___ C6H10 + ___ O2  ___ CO2 + ___ H2O
3)
___ HBr + ___ KHCO3  ___ H2O + ___ KBr + ___ CO2
4)
___ GaBr3 + ___ Na2SO3  ___ Ga2(SO3)3 + ___ NaBr
5)
___ SnO + ___ NF3  ___ SnF2 + ___ N2O3
Using the equation from problem 2 above, answer the following questions:
6)
If I do this reaction with 35 grams of C6H10, how many grams of carbon
dioxide will be formed?
7)
If I do this reaction with 45 grams of oxygen, how many grams of carbon
dioxide will be formed?
Using the equation from problem 4 above, answer the following questions:
8)
If this reaction produces 4.82 grams of NaBr, how many grams of Na2SO3
were used?
9)
If I do this reaction with 0.26 mol of GaBr3, how many moles of NaBr will
be formed?
Section 2: Stoichiometry
1. Given the following equation: 2 C4H10 + 13 O2  8 CO2 + 10 H2O,
Show what the following molar ratios (stochiometry equivalents) should
be:
a.
______C4H10 / ______ O2
b.
______ O2 / ______ CO2
c.
______ C4H10 / ______ H2O
d.
______ O2 / ______ H2O
e.
______ C4H10 / ______ CO2
2. Given the following equation: 2 KClO3  2 KCl + 3 O2. How many moles
of oxygen can be produced by letting 12.00 moles of KClO3 react?
3. How many moles of oxygen are necessary to react completely with four
moles of propane (C3H8) to form carbon dioxide and water?
4. How many moles of methane, CH4, will form if 24 grams of carbon reacts
with hydrogen gas?
5. Calculate the number of grams of sodium oxide, Na2O, that will be
provided when 5.00 moles of solid sodium react with oxygen gas?
Section 3: Stoichiometry
1. Given the following equation: 2 K + Cl2 ---> 2 KCl
a) How many grams of KCl is produced from 2.50 g of K and excess Cl2?
b) How many grams of KCl is produced from 1.00 g of Cl2 and excess K?
2. Given the following equation: Na2O + H2O ---> 2 NaOH
a) How many grams of NaOH is produced from 1.20 x 102 grams of
Na2O?
b) How many grams of Na2O are required to produce 1.60 x 102 grams of
NaOH?
3. Given the following equation: 8 Fe + S8 ---> 8 FeS
a) What mass of iron is needed to react with 16.0 grams of sulfur?
b) How many grams of FeS are produced given the amount of sulfur in
part a?
4. Given the following equation: 2 NaClO3 ---> 2 NaCl + 3 O2
a) 12.00 moles of NaClO3 will produce how many grams of O2?
b) How many grams of NaCl are produced when 80.0 grams of O2 are
produced?
5. Given the following equation: Cu + 2 AgNO3 ---> Cu(NO3)2 + 2 Ag
a) How many moles of Cu are needed to completely react with 280ml of
0.6 M solution of AgNO3?
b) If 89.5 grams of Ag were produced, how many grams of Cu reacted?
6. Molten iron and carbon monoxide are produced in a blast furnace by the
reaction of iron(III) oxide and coke (pure carbon). If 25.0 kilograms of pure
Fe2O3 is used, how many kilograms of iron can be produced?
7. The average human requires 120.0 grams of glucose (C6H12O6) per day. How
many grams of CO2 (in the photosynthesis reaction) are required for this
amount of glucose? The photosynthetic reaction is: 6 CO2 + 6 H2O --->
C6H12O6 + 6 O2
Section 4: Limiting Reagent
For the following reactions, find the following:
a)
Which of the reagents is the limiting reagent?
b)
What is the maximum amount of each product that can be formed?
c)
How much of the other reagent is left over after the reaction is complete?
1)
Consider the following reaction:
3 NH4NO3 + Na3PO4  (NH4)3PO4 + 3 NaNO3
Answer the questions above, assuming we started with 30 grams of
ammonium nitrate and 50 grams of sodium phosphate.
2)
Consider the following reaction:
3 CaCO3 + 2 FePO4  Ca3(PO4)2 + Fe2(CO3)3
Answer the questions at the top of this sheet, assuming we start with 100
grams of calcium carbonate and 45 grams of iron (III) phosphate.
Section 5: Limiting Reagent
1. Given the following reaction: (Balance the equation first!)
C3H8 + O2 -------> CO2
+ H2O
a) If you start with 14.8 g of C3H8 and 3.44 g of O2, determine the limiting
reagent
b) determine the number of grams of carbon dioxide produced
c) determine the number of grams of H2O produced
d) determine the number of grams of excess reagent left
2. Given the following equation:
Al2(SO3)3 + 6 NaOH ------> 3 Na2SO3
+ 2 Al(OH)3
a) If 10.0 g of Al2(SO3)3 is reacted with 130ml of 0.1M NaOH, determine
the limiting reagent
b) Determine the number of moles of Al(OH)3 produced
c) Determine the number of grams of Na2SO3 produced
d) Determine the number of grams of excess reagent left over in the
reaction
3. Given the following equation: (Balance the equation first!)
Al2O3 + Fe ------> Fe3O4 + Al
a) If 25.4 g of Al2O3 is reacted with 10.2 g of Fe, determine the limiting
reagent
b) Determine the number of moles of Al produced
c) Determine the number of grams of Fe3O4 produced
d) Determine the number of grams of excess reagent left over in the
reaction
Section 6: Percent Yield
1. Answer the following.
a. Write the equation for the reaction of iron (III) phosphate with
sodium sulfate to make iron (III) sulfate and sodium phosphate.
b. If I perform this reaction with 25 grams of iron (III) phosphate and
an excess of sodium sulfate, how many grams of iron (III) sulfate
can I make?
c. If 18.5 grams of iron (III) sulfate are actually made when I do this
reaction, what is my percent yield?
d. Is the answer from c reasonable? Explain.
e. If I do this reaction with 15 grams of sodium sulfate and get a
65.0% yield, how many grams of sodium phosphate will I make?
Section 7: Percent Yield Calculations
1)
Balance this equation and state which of the type of reaction taking place:
____ Mg + ____ HNO3  ____ Mg(NO3)2 + ____ H2
Type of reaction: __________________________
2)
If I start this reaction with 40 grams of magnesium and an excess of nitric
acid, how many grams of hydrogen gas will I produce?
3)
If 1.7 grams of hydrogen is actually produced, what was my percent yield
of hydrogen?
4)
Balance this equation and state what type of reaction is taking place:
____ NaHCO3  ____ NaOH + ____ CO2
Type of reaction: __________________________
5)
If 25 grams of carbon dioxide gas is produced in this reaction, how many
grams of sodium hydroxide should be produced?
6)
If 50 grams of sodium hydroxide are actually produced, what was my
percent yield?
Section 8: Percent & Theoretical Yield
1. Sulfur dioxide and zinc are produced from zinc sulfide when it reacts with
oxygen. If the typical yield is 86.78%, what mass of SO2 should be
expected if 4897 g of ZnS is used?
2. Aluminum reacts with excess copper (II) sulfate. If 1.85 g of Al reacts and
the percent yield of Cu is 56.6%, what mass of copper is produced?
3. A 15 g sample of magnesium reacts with hydrochloric acid (HCl). 46.6 g of
magnesium chloride was formed during the reaction. What was the
percent yield?
4. Titanium (IV) oxide is used as a pigment in paints and as a whitener for
paper. It, along with chlorine gas, is made by reacting titanium (IV)
chloride with oxygen gas.
a. If 3.5 mol of TiCl4 reacts with 4.5 mol of O2, what mass of TiO2
should be produced?
b. If 250.0 g of TiO2 was produced, what was the percent yield?
5. Sodium chloride is produced by the reaction between sodium metal and
chlorine gas. Suppose that 6.70 mol Na reacts with 3.20 mol Cl2.
a. What is the theoretical yield of sodium chloride? (in moles)
b. If 321.42 g of NaCl was actually produced, what is the percent yield
of the reaction?
6. Calcium carbonate decomposes when heated to produce calcium oxide
and carbon dioxide.
a. What is the theoretical yield of each product if 24.8 g CaCO3 is
heated?
b. What is the percent yield if 13.1 g CaO is produced?
Section 9: Limiting Reagent and % Yield Worksheet
1.
Consider the reaction
I2O5(g) + 5 CO(g) -------> 5 CO2(g) + I2(g)
a) 80.0 grams of I2O5 reacts with 28.0 grams of carbon monoxide, CO.
Determine the mass of iodine I2, which could be produced?
b) If only 0.160 moles, of iodine, I2 was produced.
i) what mass of iodine was produced?
ii) what percent yield of iodine was produced?
2.
Zinc and sulfur react to form zinc sulfide according to the equation.
Zn + S ---------> ZnS
If 25.0 g of zinc and 30.0 g of sulfur are mixed,
a) Which chemical is the limiting reactant?
b) How many grams of ZnS will be formed?
c) How many grams of the excess reactant will remain after the
reaction is over?
3.
Which element is in excess when 3.00 grams of Mg is ignited in
2.20 grams of pure oxygen?
What mass is in excess? What mass of MgO is formed?
4.
How many grams of Al2S3 are formed when 5.00 grams of Al is
heated with 10.0 grams S?
5.
When MoO3 and Zn are heated together they react
3 Zn(s) + 2 MoO3(s) ----------> Mo2O3(s) + 3 ZnO(s)
What mass of ZnO is formed when 20.0 grams of MoO3 is reacted
with 10.0 grams of Zn?
6.
Silver nitrate, AgNO3, reacts with iron (III) chloride, FeCl3, to give
silver chloride, AgCl, and iron (III) nitrate, Fe(NO3)3. In a particular
experiment, it was planned to mix 250ml of 1.2M AgNO3 solution
with 750ml of 0.70M FeCl3 solution.
a) Write the chemical equation for the reaction.
b) Which reactant is the limiting reactant?
c) What is the maximum number of moles of AgCl that could be
obtained from this mixture?
d) What is the maximum number of grams of AgCl that could be
obtained?
e) How many grams of the reactant in excess will remain after the
reaction is over?
7.
Solid calcium carbonate, CaCO3, is able to remove sulfur dioxide
from waste gases by the reaction (balanced as written):
CaCO3 + SO2 + other reactants ------> CaSO3 + other products
In a particular experiment, 255 g of CaCO3 was exposed to 135 g
of SO2 in the presence of an excess amount of the other chemicals
required for the reaction.
a) What is the theoretical yield of CaSO3?
b) If only 198 g of CaSO3 was isolated from the products, what
was the percentage yield of CaSO3 in this experiment?