Chapter 10 notes
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Chapter 10 NotesAll About the Mole
Objectives• Convert a quantity of a chemical between
moles, mass (g), particles, and volume.• Calculate the molar mass for any
compound.
Hi, I’m Monty Mole. I’ll be your guide for
this unit….The evil monkey
from the closet has the day off….
Molar MassStep 1: Find each atom on the periodic
table.Step 2: Find out how much each atom
weighs. (atomic mass)Step: 3 Multiply the mass by the number of
atoms in the molecule.Step 4: Add them all up!
Try it out!Find the molar masses of
the following:NaCl, SO3, H2O, PCl3
NaCl 58 g/mol
SO3 80 g/mol
H2O18 g/mol
PCl3136 g/mol
What is a Mole?•A mole is a measurement of matter.•It is used for counting things that require large numbers.•The mole is just another unit of measure like feet or grams.
The number that we use to equal a mole is called Avogadro’s number.This number is6.02 X 1023
Everything Goes Through The Mole!
• To convert from one unit to another, you must use the mole as an intermediate step.
•In other words…you might need a “two-step” conversion problem.
What is a “Two-Step” Conversion Problem?
• Two conversion factors
–One to convert from given unit to moles
–One to convert from moles to wanted unit
Mole Road Map (4 LIFE)
Mass
Representative Particles
Mole
22.4 L
1 mol
1 m
ol
22.4
L
1 mol
6.02x10 23 particles
Molar mass
1 mol
1 m
ol
Mola
r mas
s
6.02x1023 particles
1 mol
(grams) (atoms, molecules, or formula units)
Volume
of gas
(STP)
Here’s An Example
Calculate the number of molecules in 60.0 g NO2.
Given: 60.0 g NO2
1st Conversion: Molar Mass Equality
molar mass NO2 : 46.01 g46.01 g = 1 mol
2nd Conversion: Definition of Mole Equality1 mol = 6.02 x 1023 molecules
So here’s the equation:
60.0 g NO2 x 1 mol x 6.02 x 1023 molecules =
46.01 g NO2 1 mol
7.85 x 1023 molecules NO2
Another Example
Calculate the volume, in liters, of 3.24 x 1022 molecules of Cl2 (STP).
1.21 L Cl2
3.24 x 1022 molecules Cl2 x 1 mol x 22.4 L Cl2 = 6.022 x 1023 molecules 1 mol
Now let’s practice!!! HAAA AAHAHAAAA!
How many moles is 2.80 X 1024 atoms of silicon?
How many moles is 2.17 X 1023 particles of bromine?
How many moles are in 20 grams of NaCl?
Determine the volume in liters of 5 moles of hydrogen gas.
SUM IT UP!
• How many moles are in 100 grams of water?