Chapter 9 - Stoichiometry
9-1 Introduction to Stoichiometry
A. - Intro
1. Composition stoichiometry (which you studied in Chapter __) deals with the ___________ relationships
of _______________________ in __________________________.
2. Reaction stoichiometry involves ___________ relationships between ___________________ and
______________________ in a chemical reaction. It is based on chemical _______________________
and the law of __________________________ of _____________________. All reaction stoichiometry
begins with a _________________________ chemical equation.
B. - Reaction-Stoichiometry Problems
1. The problems in this chapter can be _______________________ according to the information
____________ in the problem and the information you are expected to find, the ______________________.
2. Masses are generally expressed in ______________, but you will encounter both __________- scale and
______________-scale problems with other mass units, such as ______ or ________.
3. Stoichiometric problems are solved by using _____________ from the _____________________ equation
to convert the __________________ quantity using the methods described here.
Instructor's note: Your book now lists four Problem Types. If you look at Problem Type 4, you will see that the
other three problem types are derivatives of this single larger problem.
Problem Type 4:
Mass of ___________
substance (in g)
Æ
Amount of ___________
substance (in mol)
Æ
Amount of ____________
substance (in mol)
Æ
Mass of ______________
substance (in g)
4. Solving any reaction-stoichiometry problem requires the use of a ______________ ______________ to
convert from ________________ or ______________ of one substance in a reaction to ________________
or __________________ of another substance.
5. A mole ratio is a conversion factor that relates the amounts in _______________ of any two substances
involved in a chemical reaction. This information is obtained directly from the _____________________
_____________________ ______________________.
*** On a separate piece of paper, answer Section Review Problem #3 (parts A, B and C) from page 277.
Attach your work and answers to THIS PAGE!
6. Molar mass is the mass in _______________, of one _____________ of a substance. It is the conversion
factor that relates the _____________ of a substance to the amount in _____________ of that substance.
To solve reaction-stoichiometry problems, you will need to determine molar masses using the
____________________ ________________.
9-2 Ideal Stoichiometric Calculations
A. - Intro
1. The reaction-stoichiometry calculations described in this chapter are _______________________. They tell
us the amounts of reactants and products for a given reaction under _______________ conditions, in which
_________ reactants are completely converted into ______________________.
2. Theoretical calculations serve the important function of showing the ____________________ amount of
___________________ that could be obtained before a reaction is run in the _______________________.
3. Solving stoichiometric problems requires ______________________. Using a ___________________,
______________________ approach will help you successfully solve these problems.
Study all of the examples on pages 281-287, and then work the following problems.
*** On a separate piece of paper, answer Chapter Review Problems #10, 12, 14, 16, 18 and 20 from page
296. Note that you should not assume that equations in the problems are balanced. Attach your work and
answers to THIS PAGE!
9-3 Limiting Reactants and Percent Yield
A. - Intro
1. Once one of the ____________________ is used up, no more ____________________ can be formed.
The substance that is used up first in a reaction is called the __________________ __________________.
2. The limiting reactant is the reactant that limits the amounts of the other ____________________ that can
combine and the amount of ___________________ that can form in a chemical reaction.
3. The excess reactant is the substance that is ________ _________ ________ completely in a reaction.
Study all of the examples on pages 289-291, and then work the following problems.
*** On a separate piece of paper, answer Chapter Review Problems #22, 23, 24, 25, and 26 from page 297.
Attach your work and answers to THIS PAGE!
B. - Percent Yield
1. The theoretical yield is the ________________________ amount of product that can be produced from a
given amount of ________________________.
2. In most chemical reactions, the amount of product obtained is ___________ than the theoretical yield.
3. The ________________________ amount of a product obtained from a reaction is called the actual yield
of that product.
4. Chemists are usually interested in the _________________________ of a reaction. It is expressed by
comparing the actual and theoretical yields. The percent yield is the _____________ of the actual yield to
the theoretical yield, multiplied by __________.
Write the equation for theoretical yield:
Study all of the examples on pages 293-294, and then work the following problems.
*** On a separate piece of paper, answer Chapter Review Problems #28, 29, and 30 from page 297. Attach
your work and answers to THIS PAGE!
Selected answers from the Chapter Review Problems:
b) 2.5 mol O2
10.
a) 5.0 mole H2
b) 37 g H2SO4
12.
c) 53 g Na2SO4, 14 g H2O
14.
a) 0.0104 mol Cu(NO3)2
16.
8.742 x 104 g CO, 1.262 x 104 g H2
18.
a) 42.04 mol NaOH
b) 21.02 mol Na2CO3, 21.02 mol H2O
20.
a) 3.058 mol NaHCO3
b) 3.058 mol CO2, 1.530 mol Na2SO4, 3.058 mol H2O
23.
a) 0.5 mol excess NaOH
b) 1.0 mol excess HCl
c) 0.5 mol excess H2SO4
24.
a) 2.0 mol NaCl, 2.0 mol H2O
b) 2.5 mol ZnCl2, 2.5 mol H2
c) 2.0 mol Fe2(SO4)3, 12 mol H2O
25.
b) 0.50 mol AgNO3
26.
b) 0.0104 mol Cu, 0.0209 mol AgNO3
c) 2.50 mol Cu(NO3)2, 5.00 mol Ag
d) 460. g Cu(NO3)2, 539. g Ag
b) 9.09 g excess Al(OH)3
c) 34.9 g Al2(SO4)3, 11.0 g H2O
28.
a) 75%
b) 93.8%
c) 95%
29.
a) 10.8 g
b) 5.95 g
c) 1.66 g
30.
1.02 x 104 g HNO3