Molarity
Agenda
Review
Notes on Molarity
Practice molarity
NaBr + F2 g NaF + Br2
What type of reaction?
How many spectator ions?
What is the spectator ion?
What is the net ionic equation?
Steps for Stoichiometry
Into moles
Mole ratio
Out of moles
What does
concentrated mean?
Molarity
Date:
Molarity
Definition: moles of solute dissolved per
one liter of solution.
moles
M
liter
Units are moles/liter or M
 Called molar
With nail polish and nail polish remover,
which is the solvent and which is the
solute?
What about with kool-aid?
Relation to Mole Town
Add a new town between the Valley of
Volume and DC.
Do not cross the STP dateline to get to
the Molehills of Molarity.
When you leave Mole Town DIVIDE, by
the volume in liters.
To return to Mole Town, MULTIPLY by
the volume in liters.
STP Dateline
MASS
MOLAR
MASS
MOLE TOWN
DIVIDE
6.02*1023 RP/mol
22.4 L/mol
MOLETIPLY
LITERS
VALLEY
DC
MOLE HILLS OF
MOLARITY
Hints
Remember that Molarity is a derived unit – two
units put together.
ALWAYS start problems with single unit
Separate Molarity into moles and liters, putting
only one unit in each box of the bridge.
When 3.0 moles of NaCl are
dissolved in 1.0 L of H2O,
what is the molarity?
3.0 M
When 2.0 moles of NaCl are
dissolved in 0.50 L of H2O,
what is the molarity?
4.0 M
When 5.0 moles of NaCl are
dissolved in 2.5 L of H2O,
what is the molarity?
2.0 M
When 2.0 moles of NaCl are
dissolved in 100. mL of H2O,
what is the molarity?
0.20 M
When 0.50 moles of NaCl
are dissolved in 50. mL of
H2O, what is the molarity?
10. M
When 5.8 grams of NaCl are
dissolved in 100. mL of
H2O, what is the molarity?
1.0 M
When 2.9 grams of NaCl are
dissolved in 50. mL of H2O,
what is the molarity?
1.0 M
Dilution
What does it mean to you if something
is diluted?
Dilution is changing the molarity by
adding or removing some of the solvent.
Note, the number of moles remains
constant.
M1V1 = M2V2
You are given a solution of 14.8 M
NH3. How many milliliters of this
solution do you require to give 100.0
mL of 1.00 M NH3 when diluted?
6.76 mL
You have a solution that is 1.5 M
H2SO4. How many milliliters of this
acid do you need to prepare 100.0 mL
of 0.18 M H2SO4?
12 mL
You wish to prepare 0.12 M HNO3
from a stock solution of nitric acid
that is 15.8 M. How many milliliters
of the stock solution do you require
to make up 1.00 L of 0.12 M HNO3?
7.6 mL
A chemist want to prepare 0.250 M
HCl. Commercial hydrochloric acid is
12.4 M. How many milliliters of the
commerical acid does the chemist
require to make up 1.50 L of the dilute
acid?
30.2 mL
A chemist needs to create 500 mL of
0.5 M HCl from 5.0 M HCl. How much
water must the chemist add to
complete the dilution?
450 mL of water
Partner Time
Work on the provided worksheet in the
time remaining.