NAME _______________________
Hour _____________
Date_____________
Stoichiometry
Chapter 9
Practice Assessment B
Objective 1: Interpret balanced chemical equations in terms of interacting moles,
representative particles, masses, and gas volume at STP.
Directions: Answer the following questions.
1. Write the balanced equation for the formation of gaseous dichlorine pentaoxide
from its elements. Include the “adjectives.”
2. Interpret this equation in terms of the numbers of representative particles:
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3. Interpret this equation in terms of numbers of moles
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4. Interpret this equation in terms of mass
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5. Interpret this equation in terms of volume
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Objective 2: Calculate stoichiometric quantities from balanced chemical equations
using units of moles, mass, representative particles, and volumes of gases at STP.
Directions: Solve the following problems, showing all work. Be sure to include UNITS
in the problems, as well as on your answer for credit.
1. Write the equation for the reaction of gaseous fluorine and aqueous lithium
chloride.
2. How many moles of fluorine gas are needed to form 84 moles of lithium fluoride?
3. How many grams of lithium chloride are necessary to produce 37.2 grams of
chlorine?
4. How many formula units of lithium chloride are necessary to react completely
with 394 liters of fluorine, assuming STP conditions?
5. How many liters of fluorine are necessary to produce 5.1 x 10 26 formula units of
lithium chloride?
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Objective 3: Identify and use the limiting reagent in a reaction to calculate the
maximum amount of product(s) produced and the amount of excess reagent.
Directions: Solve the following problems, showing all work. Be sure to include UNITS
in the problems, as well as on your answer for credit.
1. Magnesium reacts with iron (III) bromide in a single replacement reaction.
a. Write the balanced equation for this reaction.
b. How many grams of magnesium bromide can be produced from the
reaction of 332 grams of iron (III) bromide with 403 grams of
magnesium?
c. How many grams of excess reagent are left over, unused?
2. C2H5OH gas incompletely combusts.
a. Write the balanced equation for this reaction.
b. How many molecules of carbon dioxide are produced when 136.2 liters of
C2H5OH reacts with 411 grams of oxygen? Assume STP.
c. How many moles of excess reagent are left over, unused?
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Objective 4: Calculate the theoretical yield, actual yield, or percent yield given
appropriate information.
Directions: Solve the following problems, showing all work. Be sure to include UNITS
in the problems, as well as on your answer for credit.
1. Aluminum oxide combines with water to form a base.
a. Write the balanced equation for this reaction.
b. In an experiment, 930 grams of aluminum oxide was reacted with excess
water. If 1.35 kilograms of base are produced, what is the percent yield
of this reaction?
2. Aqueous tin (IV) nitrate reacts with aqueous sodium hydroxide.
a. Write the balanced equation for this double replacement reaction.
b. If the reaction proceeds with a 96.3% yield, how many grams of
precipitate are formed when 46 moles of tin (IV) nitrate reacts with excess
sodium hydroxide?
c. How many formula units of sodium hydroxide are consumed when the
reaction from part b proceeds?
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Objective 5: Distributed Practice:
Part 1: Write a balanced equation for the following reactions. Also, indicate what
category of reaction it is; (combination, decomposition, single-replacement, doublereplacement, or combustion.)
_______________1. Solutions of copper sulfate and barium nitrate are mixed.
Category
_______________2. Mercury (II) oxide is heated.
Category
_______________3. Silver oxide is formed.
Category
_______________4. Potassium metal is placed into nitric acid.
Category
_______________5. Propanol, CH3CH2CH2OH, is burned.
Category
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Objective 6: Distributed Practice
Part 2: Chemical and Physical Changes:
Directions:
a. Indicate if the following is a physical or a chemical change.
b. Explain the reason(s) for your choice.
c. For each chemical change, write a complete balanced equation.
a. Nickel is dropped into water:
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b. Potassium is dropped into water:
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c. A solution of ammonium carbonate is placed into a solution of magnesium
chloride:
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d. A solution of magnesium chloride is placed into a solution of sodium
sulfate.
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e. Calcium and sulfur are placed in a test tube together, and heated.
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