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Name ____________________________________________________________ Date __________________
Stoichiometry
Before You Read
Define the following terms.
mole
the SI base unit used to measure the amount of atoms, particles,
______________________________________________________________
or formula units in a substance
______________________________________________________________
molar mass
mass in grams of one mole of any pure substance
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conversion factor
a ratio of equivalent values used to express the same quantity in different units
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dimensional analysis
a method of problem-solving that focuses on the units used to
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describe matter
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law of conservation
of mass
Chapter 9
states that mass is neither created nor destroyed during a
______________________________________________________________
chemical
chemical reaction, but is conserved
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Balance the following equation.
3 Mg (s)  2 AlCl3 (aq)  2 Al (s)  3 MgCl2 (aq)
Chapter 10
Use the periodic table in the back of your text to complete the chart.
Pure Substance
Carbon
12.011
Sodium
22.990
Oxygen
15.999
Sodium carbonate
Chemistry: Matter and Change
Molar Mass
143
105.96
Science Notebook
Name ____________________________________________________________ Date __________________
Stoichiometry
Section 1 Defining Stoichiometry
Skim Section 1 of your text. Write three questions that come to mind from
reading the headings and the illustration captions.
Accept all reasonable responses.
1. ___________________________________________________________
2. ___________________________________________________________
3. ___________________________________________________________
Use your text to define each term.
stoichiometry
the study of quantitative relationships between amounts of
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reactants used and products formed by a chemical reaction
______________________________________________________________
mole ratio
a ratio between the numbers of moles of any two substances in a
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balanced chemical equation
______________________________________________________________
Define the following term.
derive
Particle and
Mole
Relationships
Use with pages 368–369.
to obtain from a specified source
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Explain the importance of the law of conservation of mass in chemical
reactions.
The law of conservation of mass states that matter is neither
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created nor destroyed in a chemical reaction. Chemical bonds in
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reactants break and new chemical bonds form to produce
______________________________________________________________
products, but the amount of matter present at the end of the
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reaction is the same as it was at the beginning of the reaction.
______________________________________________________________
Chemistry: Matter and Change
144
Science Notebook
Name ____________________________________________________________ Date __________________
Section 1 Defining Stoichiometry (continued)
Interpreting
Chemical
Equations
Use with Example
Problem 1, page 370.
Summarize Fill in the blanks to help you take notes while you read
Example Problem 1.
Problem
representative particles, moles
Interpret the equation in terms of ______________________________,
observed
mass Show that the law of conservation of mass is ___________.
and _______.
1. Analyze the Problem
C3H8(g)  5O2(g)
3CO2(g)  4H2O(g)
Known:
_____________________________________________
Unknown:
_____________________________________________
The equation in terms of molecules 
The equation in terms of moles 
_____________________________________________
_____________________________________________
The equation in terms of mass 
2. Solve for the Unknown
molecules
The coefficients indicate the number of _________________.
moles
The coefficients indicate the number of _________________.
Use the space below to calculate the mass of each reactant and each
product. Multiply the number of moles by the conversion factor, molar
mass.
moles of reactant 
grams of reactant
= grams of reactant
1 mole of reactant
moles of product 
grams of reactant
= grams of product
1 mole of reactant
Add the masses of the reactants.
44.09 g C3 H8  160.0 g O2  204.1 g reactants
Add the masses of the products.
132.0 g CO2  72.08 g H2O  204.1 g products
law of conservation of mass is observed. Does
Determine if the _____________________________
the mass of the reactants equal the mass of the products?
Yes
___________.
3. Evaluate the Answer
Each product or reactant has 4 significant figures. Your answer must
have 4 significant figures.
Chemistry: Matter and Change
145
Science Notebook
Name ____________________________________________________________ Date __________________
Section 1 Defining Stoichiometry (continued)
Mole ratios
Use with pages 371–372.
Examine Relationships between coefficients can be used to write
mole ratios
conversion factors called ___________________.
Example
Given the equation 2KClO3(s)
2KCl(s) + 3O2(g)
mole ratio with the other substances in the
Each substance forms a _____________
reaction.
Write the mole ratios that define the mole relationships in this equation.
(Hint: Relate each reactant and each product to each of the other
substances.)
2 mol KCIO3
2 mol KCl
and
2 mol KCIO3
3 mol O2
3 mol O2
2 mol KCl
and
2 mol KCIO3
2 mol KCIO3
3 mol O2
2 mol KCl
and
3 mol O2
2 mol KCI
You Try It
Draw arrows with colored pencils that show the relationships of the
substances in this equation.
Write the mole ratios for the above equation.
1 mol C2H4
3 mol O2
3 mol O2
1 mol C2H4
2 mol CO2
3 mol O2
2 mol H2O
3 mol O2
Chemistry: Matter and Change
146
and
1 mol C2H4
and
3 mol O2
and
and
2 mol CO2
2 mol CO2
2 mol CO2
1 mol C2H4
2 mol H2O
2 mol CO2
and
1 mol C2H4
and
3 mol O2
2 mol H2O
2 mol H2O
and
2 mol CO2
and
2 mol H2O
2 mol H2O
1 mol C2H4
Science Notebook