Name: _______________________________________ Period: __________ Score: __________
LEARNING GUIDE 32:MOLAR MASS
EDITORS
Tymon, Aaron, Francisco
STATE CONTENT STANDARDS
3. d. Students know how to determine the molar mass of a molecule from its chemical formula
and a table of atomic masses and how to convert the mass of a molecular substance to moles,
number of particles, or volume of gas at standard temperature and pressure.
MAJOR CONCEPTS
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Students understand the definition of molar mass
Compare and contrast the atomic mass of an element and its molar mass
Students learn to convert between moles and mass of a given sample of a chemical compound
VOCABULARY
Define each vocabulary word
1. Molar mass-the mass in grams of one mole of a compound
READING
Chapter 6.4
Part I: Important Facts (List seven important facts found during the reading)
Section 6.4
1. _______________________________________________________________
2. _______________________________________________________________
3. _______________________________________________________________
4. _______________________________________________________________
5. _______________________________________________________________
Place your answers to problem set 32 in your 3-ring binder, Unit 3.
Name: _______________________________________ Period: __________ Score: __________
6. _______________________________________________________________
7. _______________________________________________________________
Part II: Summaries
Using one paragraph per section, summarize the two sections you just read.
Section 15.1
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READING GUIDE
Complete Reading Guide 32
CHAPTER 6.4
1. What is a chemical compound?
2. What does each methane (CH4) molecule contain?
3. What does each mole of methane (CH4) contain?
4. How do you find the mass of 1 mole of methane?
UNIT 2: READING GUIDE 32
Name: _______________________________________ Period: __________ Score: __________
5. Define molar mass.
6. How do you obtain the molar mass of a compound?
7. Sometimes, for ionic compounds, the term “_______________ __________” is used instead of
“molar mass.”
8. Read example 6.5 question and solution on page 166. Complete self-check Ex. 6.4.
9. Calculate the molar mass (mass of one mole) of each compound below.
a. KMnO4 __________
b. KCl __________
c.
Na2SO4 __________
d. Ca(NO3)2 __________
e. Al2(SO4)3 __________
f.
(NH4)3PO4 __________
g. CuSO4  5H2O __________
h. Mg3(PO4)2 __________
i.
Zn(C2H3O2)2  2H2O __________
j.
Zn3(PO4)2  4H2O __________
k.
H2CO3 __________
l.
Hg2Cr2O7 __________
UNIT 2: READING GUIDE 32
Name: _______________________________________ Period: __________ Score: __________
m. Ba(ClO3)2 __________
n. Fe2(SO3)3 __________
o.
NH4C2H3O2 ________
LECTURE NOTES
Combine your notes from class with the notes on TheChemBook. Use the Cornell Notes
Strategy to review your notes each night (5 min.).
I. The Mass of a Mole of a Compound
A. Formula Mass
1. The sum of the average atomic masses of all the atoms represented in the formula of a
molecule, formula unit, or ion
Formula Mass of glucose, C6H12O6 :
C = 12.01 amu 6 x 12.01 amu = 72.06 amu
H = 1.01 amu 12 x 1.01 amu = 12.12 amu
O = 16.0 amu 6 x 16.00 amu = 96.0 amu
Formula Mass = 180.18 amu
B. Molar Masses
1. A compound’s molar mass is numerically equal to it formula mass, but expressed in
units of grams/mole (g/mol)
Molar Mass of glucose, C6H12O6 = 180.18 g/m
Place your answers to problem set 32 in your 3-ring binder, Unit 3.
Name: _______________________________________ Period: __________ Score: __________
I.
The Mole-Mass Relationship
A. Converting moles of compound to grams
Amount in moles x molar mass (g/mol) = Mass in grams
B. Converting grams of compound to mass
Mass in grams x
1 = Amount of moles
molar mass (g/mol)
II.
I.
The Mole-Volume Relationship
A. Standard Temperature and Pressure (STP)
1. Standard Temperature = 0o or 273 K
2. Standard Pressure = 101.3 kPa or 1 atmosphere
B. Standard Molar Volume
1. The volume occupied by one mole of any gas at STP
2. 1 mole of any gas at STP occupies 22.4 liters of volume
C. Determine Densities
1. Density = m/v
2. Density at STP = mass of one mole / 22.4 liters
Writing and Using Mole Ratios
A. Mole Ratios
1. A conversation factor that releases the amounts in moles of any two substances
involved in a chemical reaction
2. Mole ratio is used to convert:
Given moles =unknown moles
B. Molar Mass
1. Molar mass of compounds and elements is used to convert:
Given mass = given moles
And
Place your answers to problem set 32 in your 3-ring binder, Unit 3.
Name: _______________________________________ Period: __________ Score: __________
Unknown moles = unknown mass
II.
Calculations Involving Moles and Mass
A. Four problem Types, One Com on Solution
Given mass = given moles = unknown moles = unknown mass
1. Given and unknown quantities are in moles
2. Given is an amount in moles and the unknown is a mass (usually in grams)
3. Given is a mass in grams and the unknown is an amount in moles
Given is a mass in grams and the unknown is a mass in grams
http://www.thechembook.com/wiki/index.php/Molar_Mass
Chemistry book pages 165- 168
FOCUS QUESTIONS
1. How many moles of atoms of each element are present in the following amounds of each
compound?
a. 3 mol NH3
b. 0.25 mol H20
c. 5.0 mol H2SO4
2. Determine the molar mass of each of the following. Show your work.
a. NH3
_____________
b. H2O
_____________
c. H2SO4
_____________
d. Ca(NO3)2 _____________
Place your answers to problem set 32 in your 3-ring binder, Unit 3.
Name: _______________________________________ Period: __________ Score: __________
JOURNAL
What points in the material strike you as important?
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Have you learned anything new? If so, what did you learn?
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Do you have any questions about what you learned?
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How does what you learned relate to other information that you have learned in this course?
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How did the class work stimulate your thinking?
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Place your answers to problem set 32 in your 3-ring binder, Unit 3.