Molarity
ICS III
Week 7
Kool Aid
•Ingredients in Kool Aid
•Water
•Sugar
Kool Aid

Kool Aid is a solution
– Mixture of solutes dissolved in solvents
– Solute
 Dissolved particles in a solution
 sugar
– Solvent
 The dissolving medium of a solution
 water
Grams per Liter

represent the mass of solute divided by
the volume of solution
– 50g sugar/ 100 g water
 The ratio would be 1:2
– 1 part sugar to 2 parts water
Molarity
moles of solute divided by liters of
solution.
 Calculate the number of moles of
dissolved solute and divide by the volume
in liters of the total solution, yielding units
of moles per liter.

Grams per liter
Moles per liter
Grams of solute
moles of solute
Liters of solvent
Liters of solvent
g/L
Grams per liter
M
Molarity
180 g C6H12O6
1 L H2O
= 180 g/L
1 mol C6H12O6
1 L H2O
180 g C6H12O6 = 1 mol C6H12O6
= 1M solution
Molarity of Pepsi Cola
12 fl oz = 355 ml = .335 L
 What is the g/L??

– 41g/.335 L = 122 g/L

What is the Molarity
– 1 mole = 180 g sugar
– 41 g = .23 mol sugar
.23 mol sugar
= .69 M
.335 L Water
1.
How many moles of HNO3 are needed to
prepare 5.0 liters of a 2.0 M solution of
HNO3?
a)
b)
c)
d)
2.5
5
10
15
=
X moles
Parts Per Million (ppm)

a ratio of one part of solute to one million parts
of solvent, is usually applied to very dilute
solutions.
– Chorine in a pool
– 7.2 – 7.4 ppm

To calculate parts per million
– determine the mass of solvent and solute
– divide the mass of the solute by the total mass of the
solution.
– Multiply by 106 (1 million) and expressed as parts per
million (ppm).
Practice Problem/ ppm

a)
b)
c)
d)
The Dead Sea is the saltiest sea in the
world. It contains 332 grams of salt per
1000 grams of water. What is the
concentration in parts per million (ppm)?
.332 ppm
Grams
332 ppm
332solute
g
Grams
solvent
1000
g
33,200 ppm
332,000 ppm
=
332,000
332
X 106
Percent Composition
The ratio of one part of solvent to one
hundred parts of solvent and is expressed
as a percent.
 To calculate percent composition

– determine the mass of solvent and solute
– divide the mass of the solute by the total
mass of the solution.
– Multiply by 100 and expressed as a percent.
Percent Composition

a)
b)
c)
d)
The Dead Sea is the saltiest sea in the
world. It contains 332 grams of salt per
1000 grams of water. What is the
percent composition?
.0332%
Grams
.332%
332solute
g
Grams
solvent
1000
g
33.2%
332%
= 33
3322
X 100
Combine Both Concepts

a)
b)
c)
d)
What is the concentration of a 4%
solution converted to parts per million
•Step 1: Convert from percent
(ppm)
to concentration
4,000 ppm
•4%/100
40,000 ppm
•.04
400,000 ppm
•.04 x 106 (1,000,000)
4,000,000 ppm