HONORS CHEMISTRY
Jan 30, 2013
Review
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Gp 1: +1
Gp 2: +2
Gp 3: +3
F = -1
H = +1
**O = -2
Element = 0
** Gp 6 = -2 (unless paired with O or halogens)
** Gp 7 = -1 (unless paired with O or halogens)
Brain Teaser
H2C2O4 +KMnO4 CO2 + K2O + Mn2O3 + H2O
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Which atom is oxidized? Which atom is reduced?
Find the oxidation number of
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Mn3(PO4) 2
What is the molar mass of Fe(OH) 3?
Agenda
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Brain Teaser
Grade Homework
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Unit 7 Notes
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Oxidation-Reduction Worksheet
Review Oxidation-Reduction
Mole Conversions
“How many moles?!” Project Info
Homework
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Bring Supplies Wednesday/Thursday
Oxidation-Reduction Quizlet –
Wednesday/Thursday
Moles Worksheet
Mole Conversions
Are these moles?
What is a mole?
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A unit of measurement
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Since the numbers in chemistry are so small,
we use a “preferred unit of measurement”
(mole) to represent the small number
What are the units of measurement?
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"that equal number" of atoms randomly chosen.
the number of atoms in the atomic weight in g of any
element.
the number of atoms in 16 g of oxygen, in 4 grams of
He, in 32 g of sulfur, etc.
the number of molecules in the molecular weight, in
grams, of any compound.
the number of molecules in 18 g of water, in 40 g of
lithium carbide.
Much later, a mole, that equal number, was found to
be 6.022 x 1023(representative particles).
Examples
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1 mole (or abbr. mol) = 12.011 g of Carbon
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1 mol of Carbon = 6.02 x 1023 atoms of C
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1 mol of H2O = 6.02 x 1023 molecules of
water
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1 mol of NaCl = 6.02 x 1023 units of NaCl
Figure 8.1: All these samples of pure elements contain the
same number (a mole) of atoms: 6.022 x 1023 atoms.
Copyright © Houghton Mifflin Company.All rights reserved.
8–5
Moles in mass
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1 mole can equal the atomic weight of an
element.
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1mol of C = 12.011g of C
1 mole can equal the atomic weight of a
compound
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1mol of CO = 12.011g of C + 15.99 g of O
= 28.0 g of CO
Practice Problems
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How many grams of Cu are in 1.20 mol of
Cu?
How many moles are in 70g of Cl?
Moles in compounds
Let’s say you have water aka. H2O
How many moles of Hydrogen atoms(ions) are
in water?
 Ask yourself how many individual atoms of
Hydrogen do you see in water?
 Did you say 2???
 Is that your final answer?
 You are correct! So how many mols of
Oxygen atoms do you see?
Moles in an equation
2 H2 + O2  2H2O
How many moles of Hydrogen molecules are in
the reactants?
*Coefficients serve as the number of moles too!
Therefore, there are 4 mols of Hydrogen gas
NOPE!!!! Fooled you.. 2 mols of Hydrogen gas
Molecules
Atoms
Units
Mole Conversion
Boomerang
Mole Conversions
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Mass to mole or vice versa:
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How many moles are in 24 g of Carbon?
Look at the boomerang:
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Start with the given: 24 g (mass) of C
What do you want in the end? Moles of C
Use the conversion factor given:
1 mole
Atomic mass
24 g of C x 1 mol of C = 2.0 mol of Carbon
12.011 g of C
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White Boards
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Given 200 g of water, how many mols of
water do you have?
How many grams of carbon monoxide are in
1.5 mols of carbon monoxide?
More conversion
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Mole to atoms/molecules/particles or vice versa
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How many atoms are in 2.00 mols of Carbon?
Look at the boomerang:
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Where do you begin? (the given: mols)
What do you need in the end? (atoms: particles)
What’s the conversion factor?
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6.02 x 1023 Atoms of C
1 Mols of C
2.00 mols of C x 6.02 x 1023 atoms of C = 1.20 x 1024 atoms C
1 mol of C
White boards
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How many molecules of oxygen gas are in
3.0 mols of Oxygen gas?
How many mols of Oxygen gas are in
4.67 x 1024 molecules of Oxygen gas?
More conversion
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Mole to volume of gas or vice versa
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What is the volume occupied by 2 mols of hydrogen gas?
Look at the boomerang:
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Where do you begin? (the given: mols)
What do you need in the end? (volume of gas)
What’s the conversion factor?
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22.4 L of H2
1 Mols of H2
2.00 mols of H2 x 22.4 L of H2 = 44.8 L of H2
1 mol of H2
White boards
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Convert 4.38 moles of He to liters
Convert 3.01 L of N to moles
Practice
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Must show work (dimensional analysis)
How many grams are in 1 mol of Mercury?
Given a 1.5 mols of carbon dioxide, how
many molecules of carbon dioxide do you
have?
Mole Conversions
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2 Step Process (Refer to chart)
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How many atoms are in 2L of Oxygen gas?
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Where do you begin? (the given: Volume)
What do you need in the end? (atoms)
How many conversion factors do we need?
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Volume to moles
Moles to atoms
2 L x 1 mole x 6.02x1023 atoms of O2 = 5.38 x 102
22.4 L
1 mole
atoms
Practice
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How many formula units are there in 98 g of
Potassium hydroxide?
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How many grams are there in 4 x 1024
molecules of Iron (II) chloride?
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How many molecules are there in 15 L of Cl2
gas?
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What is the volume of gas (in L) in 5 x 1025
molecules of O2?
Partner BrainQuest
Determine the oxidation number of each
element in the following compounds:
(a) BaO
(b) Fe3(PO4) 2
(c) (NH4) 2O
(d) CS2
 Determine which element is oxidized and
which is reduced when lithium reacts with
nitrogen to form lithium nitride.
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6Li + N2  2Li3N
Pogile Activity
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Understand what is meant by percent
composition by mass of a compound
Ability to determine the percent composition
by mass of a compound
Pogile Activity
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Task 1
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Percent of boys present today
Task 2
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Determine the percent of sugar in the gum
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Task 3
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DO NOT place gum directly on the electronic balance!!!
Dispose gum properly!
Methane
Exercises