Are you ready for your quiz tomorrow?
• Take out a scratch sheet of paper, a
pencil/pen, and a calculator
1. A gas at 3 atmospheres has a solubility of 17 g/L. If
we changed the pressure to 20 atmospheres, what
is the gas’s solubility?
2. We have a 30% solution of sodium chloride. We
made this solution by adding 57 grams of salt to how
many grams of water?
3. What is the concentration of a solution made from
170 grams of BaCl2 and 300 grams of water?
4. We have 256 grams of a 30% sodium chloride
solution. How many grams of salt and how many
grams of water were used to make the solution?
5. Don’t forget about your solubility curves!! You’ll see
these types of problems tomorrow.
1. A gas at 3 atmospheres has a solubility of 17 g/L.
If we changed the pressure to 20 atmospheres,
what is the gas’s solubility?
S1 S 2

P1 P 2
17 x

3 20
3x = 340
x = 113 g/L
2. We have a 30% solution of sodium chloride.
We made this solution by adding 57 grams
of salt to how many grams of water?
solute
100  %
solution
57
100  30
x
x 190 g of solution
solution  solute  solvent
190  57  water
133 g  water
3. What is the concentration of a solution made
from 170 grams of BaCl2 and 300 grams of
water?
solute
100  %
solution
solute
 100  %
solute  sovlent
170
100 
(170  300)
170
100  36.2%
470
4. We have 256 grams of a 30% sodium chloride
solution. How many grams of salt and how
many grams of water were used to make the
solution?
solute
100  %
solution
x
100  30
256
x  76.9 g of solute (salt )
solution  solute  solvent
256  76.9  water
179.1g  water
• Sometimes the terms diluted and concentrated
are not specific enough
• Just like in a cooking recipe, in chemistry lab you
may need a certain amount to make your
experiment work properly
Molarity (M)
• Molarity, M, molar concentration
• 2 M = pronounced as 2 molar
• Molarity is another way to express concentration as
moles per liter
moles of solute
Molarity 
Liters of solution
• This means you need to remember your flow chart
so that you can convert from grams to moles if
grams is given in the problem!
÷
Mass
(grams)
Molar Mass
Grams / mole
x
Avogadro’s
Number
Moles
6.02 x 1023
particles/mole
÷
x
Particles
(atoms or
molecules)
Remember if we’re given grams to get to moles we do
grams
molar mass
• We can manipulate the molarity equation…
moles solute
Molarity 
Liters of solution
grams
moles 
molar mass
grams
molar mass
Molarity 
Liters of solution
What is the molarity of a solution containing 58
grams of sodium chloride in 1 liter of water?
grams
molar mass
Molarity 
Liters of solution
58
(23  35.5)
Molarity 
1
1M
Calculate the molarity of 100 mL solution containing
50 grams of H2SO4.
• Don’t forget that we must use Liters!
• Remember King Henry Died Unexpectantly Drinking Chocolate
Milk– KHDUDCM
• 100 mL = 0.1 L
grams
molar mass
Molarity 
Liters of solution
50
(2  32.1  4 16)
Molarity 
0.1
50
Molarity  98.1
0.1
5.1 M
How many grams of salt would be dissolved in 1 L
of a 0.5 M solution of NaCl
moles of solute
Molarity 
Liters of solution
x
0 .5 
1
x  0.5 moles of NaCl
0.5  (23  35.5)  29.25 g NaCl