Objective: What do you do if you are asked to convert between two units, and neither one is the mole? When calculating chemical quantities, everything goes through the ________________________ If neither of your units is a mole, you will need a ____________-step conversion problem. One ________________ ______________ to go from the given units to __________________, and a second conversion factor to go from moles to the ______________________ units. You know we are talking about MASS if the units are _________________. You know we are talking about VOLUME if the units are ________________. You know we are talking about particles if the units are ________________, _________________, or _________________ ______________.
Chapter 10 notes
Chapter 10 Notes
All About the Mole
• Convert a quantity of a chemical between
moles, mass (g), particles, and volume.
• Calculate the molar mass for any
Hi, I’m Monty Mole.
I’ll be your guide for
The evil monkey
from the closet has
the day off….
Step 1: Find each atom on the periodic
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
NaCl, SO3, H2O, PCl3
What is a Mole?
•A mole is a
•It is used for
that require large
•The mole is just
another unit of
measure like feet
that we use
to equal a
6.02 X 1023
Everything Goes Through The Mole!
• To convert from one unit to
another, you must use the
mole as an intermediate step.
might need a
What is a “Two-Step” Conversion
• Two conversion factors
–One to convert from given
unit to moles
–One to convert from
moles to wanted unit
Mole Road Map (4 LIFE)
(atoms, molecules, or formula units)
Here’s An Example
Calculate the number of molecules in 60.0 g NO2.
Given: 60.0 g NO2
Conversion: Molar Mass Equality
molar mass NO2 : 46.01 g
46.01 g = 1 mol
Conversion: Definition of Mole Equality
1 mol = 6.02 x 1023
So here’s the equation:
60.0 g NO2 x 1 mol x 6.02 x 1023
46.01 g NO2 1 mol
7.85 x 1023
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
How many moles is 2.17 X 1023
particles of bromine?
How many moles are in 20 grams of
Determine the volume in liters of 5
moles of hydrogen gas.
• How many moles
are in 100 grams
Calculating Percent Composition
• Step 1: Find the atomic mass of each
element in the compound from the
• Step 2: Multiply each mass by the number
of atoms in the compound.
• Step 3: Add all the numbers together.
• Step 4: Divide each individual number by
the total weight and multiply by 100.
• Find the percent composition of PbCO4
Pb 207 1 207
C 12 1 12
O 16 4 64
283 total weight
• When no formula is given, take the
numbers that are given and add them
together to get a total.
• Divide each number by the total and
multiply by 100 to get the percent.
• What is an empirical formula?
• This is a formula that gives the lowest
whole number ratio of atoms in a
• It’s similar to reducing fractions.
Calculating Empirical Formulas
• Step 1: Start with the number of grams of
each element in the compound. If it is a
percent, then the percent equals the
• Step 2: Convert each mass to moles. Use
what you know about conversions. (Hint:
You are dividing by the atomic mass from
the periodic table!)
• Step 3: Divide by the LOWEST number.
• Step 4: If you get a number that’s too far
to round, multiply every number to get a
• Step 5: The number for each element
equals the number in the formula.
• Molecular formula is similar to empirical
• It is a multiple of the empirical formula and
reflects the actual chemical formula.
• Step 1: If the empirical formula isn’t given,
calculate this first.
• Step 2: Find the molar mass of the
• Step 3: Using the molecular mass given,
divide the empirical formula’s weight by
the molecular mass.
• Step 4: Multiply that answer into the
Bring me 1