Chapter 10 Notes
Honors Chemistry
Chapter 10: Chemical Quantities
Section 1 Notes – The Mole: A Measurement of Matter
(Read pages 287-296)
Mole


chemist _______________ for number of _______________
equals _______________ number = _______________
Representative Particles

atoms – _______________

molecules – _______________ _______________

formula units – _______________ _______________

ions - _______________ _______________
Conversions
 _____ mole equals
o _______________ atoms, molecules, formula units, ions, things
Practice Problems (Do Together)
3. How many moles is 2.80 x 1024 atoms of Si?
4. How many moles if 2.17 x 10 23 representative particles of bromine?
5. How many atoms are in 1.14 mol SO3?
6. How many moles are in 4.65 x 24 molecules of NO2?
Additional Practice Problems
1. How many moles are equal to 9.03 x 1024 atoms of mercury?
2. How many atoms are in 1.00 mole of sucrose, C12H22O11?
3. How many atoms of O are in 3.65 moles of C12H22O11?
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Chapter 10 Notes
Honors Chemistry
Molar Mass
 mass of _____ mole of a _______________
o _______________ or _______________
 Units
o _______________ (grams per mole)
o _______________ (atomic mass unit)
How do we find the mass of an element?
 _____________ _____________ on the _______________ _______________
 example:
o mass of ______ = __________ g/mole
How do we find the mass of a compound?
 _______ _______ the _______________ of all the _______________ in the _______________
 example: mass of KMnO4
Practice Problems
1. Find the molar mass of PCl3. Also, name the compound.
2. What is the mass of 1.00 mol of sodium hydrogen carbonate (hint, write the formula first)?
Additional Practice Problems
1. What is the mass, in grams, of 1.72 mol CaCl2?
2. Determine the mass of one mole of each of the following compounds and give their names.
Compound
Mass in One Mole
a. CO2
b. SO3
c. NaOH
d. Al2(SO4)3
e. Ba(NO3)2
Book Work: Page 296 #9-15
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Name
Chapter 10 Notes
Honors Chemistry
Section 2 Notes – Mole-Mass and Mole Volume Relationships
(Read pages 297-303)
ONE Mole equals THREE things:
1. _______________ particles (atoms, molecules, formula units, ions)
2. _______________ _______________ of a substance (in _______________)
a. _______________
b. _______________
3. __________ liters
a. _______________ only at STP
i. STP = standard _______________and _______________
Fill in your mole map as we go through this section!
The Mole Road Map – There are 3 conversions!
1. 1 mole = ___________________________________________________
2. 1 mole = ___________________________________________________
3. 1 mole = ___________________________________________________
Practice Problems (Do Together)
16. Find the mass, in grams, of 4.52 x 10-3 moles of C20H42.
17. Calculate the mass, in grams, of 2.50 moles of iron (II) hydroxide.
18. Find the number of moles in 3.70 x 10-1 g of boron.
19. Calculate the number of moles in 75.0 g of dinitrogen trioxide.
Additional Practice Problems
1. Calculate the mass in grams for 0.250 mol of each of the following compounds:
a. Sucrose (C12H22O11)
b. Sodium chloride
c. Potassium permanganate
The Mole-Volume Relationship
 _______________ hypothesis states that _______________ _______________ of _______________ at
the same _______________ and _______________ contain _______________ numbers of
_______________.
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Chapter 10 Notes
Honors Chemistry
Practice Problems
20. What is the volume of the following gases at STP?
a. 3.20 x 10-3 moles of CO2
b. 3.70 moles of N2
21. At STP, what volume do these gases occupy?
a. 1.25 moles He
b. 0.335 moles C2H6
Density
 D=
Calculations using density and molar mass
molar mass = density _____ 22.4 L
(units = _______________ )
density = molar mass _____ 22.4 L
(units = _______________ )
Practice Problems (Do Together)
22. A gaseous compound composed of sulfur and oxygen, which is linked to the formation of acid rain, has a
density of 3.58 g/L at STP. What is the molar mass of this gas?
23. What is the density of krypton gas at STP?
Additional Practice Problems
1. At STP, what volume is occupied by each of the following gasses?
a. 1.34 mol SO2
b. 2.45 x 10-3 mol H2S
2. A gas has a density of 0.902 g/L. What is the molar mass of this gas?
3. What is the density of oxygen gas, O2, at STP?
Book Work - Page 303 #24-31
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Chapter 10 Notes
Honors Chemistry
Section 3 Notes – Percent Composition and Chemical Formulas
(Read pages 305-312)
What does percent mean?
 _______________ of a _______________
Percent Composition


Percent Composition =
Unit is _________
Practice Problems
32. A compound is formed when 9.03g Mg combines completely with 3.48g N. What is the percent
composition of this compound?
33. When a 14.2g sample of mercury (II) oxide is decomposed into its elements by heating, 13.2g of Hg is
obtained. What is the percent composition of the compound?
34. Calculate the percent composition of these compounds.
a. Ethane (C2H6)
b. Sodium bisulfate (NaHSO4)
Additional Practice Problems
1. What is the percent composition of the compound formed when 2.70 g of aluminum combine with
oxygen to form 5.10 g of aluminum oxide?
2. Calculate the percent composition when 13.3 g of Fe combine completely with 5.7g O.
5
Chapter 10 Notes
Honors Chemistry
3. Determine the percent composition of the following oxides:
a. Fe2O3
b. Na2O
4. Calculate the grams of oxygen in 90.0 g of Cl2O.
This information is from Chapter 15, but it makes more sense to talk about it with percent composition. So
refer to Chapter 15, Section 2 if you have hydrate questions.
Hydrates – a compound containing ___________
Naming Hydrates
 Name the ___________ ___________
 Determine the ___________ for ___________, followed by ___________
 Example:
o Na2CO3 • 10H2O
o ________________________________________________
Writing Hydrate Formulas
 Write the ___________ of the ___________ compound
 Determine the appropriate number of ___________ molecules based on the ________ ________
 Example:
o Magnesium sulfate heptahydrate
o __________________________
Determining the percent of water in a hydrate
 Equation:

Determine the percent by mass of water in sodium carbonate decahydrate,
Na2CO3 • 10H2O.
Practice Problem
 What is the percent by mass of water in copper (II) sulfate pentahydrate?
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Chapter 10 Notes
Honors Chemistry
Determining the Formula of a Hydrate from Percent Water
1. Find the _______________ of water driven off.
2. Convert the _______________ of the anhydrate to _______________.
3. Convert the mass of _______________ to moles.
4. Find the mole _______________ to mole anhydrate _______________.
Example
A calcium chloride hydrate has a mass of 4.72 g. After heating for several minutes, the mass of the anhydrate is
found to be 3.56 g. Use this information to determine the formula of the hydrate.
Empirical Formulas
 _______________ whole-number ratio of _______________ in a compound
 may or may not _______________ as a _______________ substance (you don’t need to know)
Molecular Formula
 simple whole-number _______________ of the _______________ formula
o might be the _______________ as the empirical formula
 _______________ exists as a _______________ compound
 to find the multiplier:
o multiplier =
Reminder: Sometimes you have to find the _______________ Formula _______________ you can calculate
the _______________ Formula!
Finding Empirical Formula from Percent Composition
1. _______________ to _______________
a. Convert the percent to a mass (No _____________)
2. _______________ to _______________
a. Convert the masses to moles (Divide by _____________)
3. _______________ by _______________
a. Divide each of the mole values by the _______________ mole value.
4. _______________ till _______________
a. Each number should be a _______________ number.
b. Not always _______________.
Example using the rhyme:
 Given
o 35.4% Cr
o 38.1% O
o 26.5% K
 Find the empirical formula of the compound
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Chapter 10 Notes
Honors Chemistry
1. Percent to Mass
2. Mass to Mole
3. Divide by Small
4. Multiply till Whole
Finding Molecular Formula from Empirical Formula
 You must be given the ______________ _______________of the compound.
 Find the _______________:
o Remember: multiplier =


Multiply each of the _______________from the _______________formula by the _______________. This
new number is the _______________in the _______________ formula.
This _______________ or _______________ _______________ be the same as the
_______________formula.
Finding MF from EF Example
1. What is the molecular formula of a compound with the empirical formula CH and a molar mass of 104.08
g/mol?
Practice Problems
1. What is the empirical formula of each of the following compounds?
a. 36.1 % Ca, 63.9 % Cl
b. 3.7 % H, 44.4 % C, 51.9 % N
2. What is the molecular formula of a compound with the empirical formula CClN and a molar mass of
184.5?
Book Work - Page 312 #40-46
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