Which salt solution has the greatest
concentration?
[ ] is a measure of the amount of solute in a given amount of solution
Beaker A
3 molecules
100 mL solution
Beaker B
5 molecules
100 mL solution
Beaker C
7 molecules
200 mL solution
Ppm, % Composition, Molarity ,
and pH
Get out your calculator!
1. A bottle contains 500. mL of water. If this
solution has 15.5 mL of pure hydrogen
peroxide, what is the concentration of
hydrogen peroxide in this solution?
amount of solute
% Compositio n 
X 100
amount of solute  amount of solvent
% Hydrogen Peroxide 
% Hydrogen Peroxide 
15.5 mL
X 100
15.5 mL  500 mL
15.5 mL
X 100  3.01%
515.5 mL
percent composition = amount solute
100
amount solution
2. I dilute 10.0 mL of HBr to make a 42.5% HBr
solution. What will the total volume of the
solution be?
42.5 = 10.0 ml
100
x
42.5 x
= ___________
10.0 ml (100)
______
42.5
42.5
x = 23.5 ml
Hmmmm…..how much of the solution is just
solvent (water)?
percent composition = amount solute
100
amount solution
3. If a concentrated solution of hydrogen
peroxide has a percent composition of 65%, how
many mL of pure hydrogen peroxide would be
contained in a 0.750 L solution?
65 =
x_
65 (0.750 L) =
x
100
0.750 L
100
0.49 L = x
0.49 L (1000 ml) = 490 ml
1L
percent composition = amount solute
100
amount solution
4. What mass (in grams) of NaCl is necessary to
make a 5.0% NaCl solution using 82 ml (82
GRAMS) of water? JUST WATER!
5.0 = x _
100
x + 82
5.0 (x + 82) = x (100)
5.0x + 410 = 100x
410 = 95x
x = 4.3 grams NaCl
ppm
106
= amount solute
amount solution
5. For cavity prevention, the recommended concentration of
fluoride ions in our drinking water is 0.7 to 1.2 parts per million
(ppm). Too much fluoride can result in discolored teeth. If the
concentration of F- in Orange County is 0.85 ppm, what mass of
fluoride would be contained in a 7.2 gram tap water sample from
and OCHSA bathroom?
0.85 =
106
x grams F7.2 gram
0.85 (7.2 gram ) = x grams F106
6.1 x 10-6 g F-
ppm
= amount solute
106
amount solution
6. What is the concentration of mercury (in ppm)
if 3 grams mercury is found in a 15 kg sample of
ocean water?
15 kg (1000g) = 15000 g
1kg
x ppm
= 3g
106
15000 g
x = 200 ppm
x ppm = 3 g (106 )
15000 g
ppm
= amount solute
106
amount solution
7. What mass of mercury (in grams) would be
contained in a 40.0 kg sample of ocean water
at this same concentration?
40.0 kg (1000g) = 4 x 104 g
1kg
200 ppm = x g Hg
106
4 x 104 g
200 ppm(4 x 104 g) = x = 8 g Hg
106
El Agua Cristal es mejor porque ha sido filtrada por la naturaleza
durante décadas, adquiriendo de manera natural los minerales
necesarios para un perfecto equilibrio del organismo.
Análisis químico mg/l (ppm)
La NSF certifica que Agua Cristal
Calcio
11.9
cumple con las más estrictas
Magnesio
10.3
normas de calidad requeridas
0.1
por la FDA de los Estados Unidos. Hierro menos de
Flúor menos de
0.1
Sodio
7.0
Un envase de 600 ml contiene:
pH
6.63
Potasio
4.7
Sulfatos
4.0
Dureza del calcio
29.7
Dureza del
35.7
magnesio
Alcalinidad total
67.8
S.T.D
184
8. You have 0.800 L of a 0.500 M HCl solution. How
many moles of HCl does this solution contain?
mol
M
L
mol  M x L
mol  0.5 M x 0.8 L
mol  0.400 mol HCl
9. You have 3.50 L of solution that contains 90.0 g
of sodium chloride, NaCl. What is the molarity
of that solution?
90.0 g NaCl
(1 mol NaCl)
= 1.54 mol NaCl
(58.44 g NaCl)
mol
M
L
1.54 mol NaCl

3.50 L
 0.440 M NaCl
mol
 0.440
NaCl
L
10. What volume of a 0.500 M solution of HBr is
needed for a reaction that requires 32.5 g of HBr?
32.5 g HBr
(1 mol HBr)
80.91 g HBr
mol
M
L
mol
L
M
= 0.402 mol HBr
0.402 mol HBr

0.500 M
 0.804 L of solution
2 problems, 5 minutes!
The answers should add up to 82.6
11. Calculate the volume of water (in ml) needed
to make a 4.00 M solution using 50.6 grams
barium fluoride?
ANSWER: 72.1 ml (formula = BaF2)
12. How many grams of potassium iodide must be
added to 0.450 L water to make a 0.140M
solution of this salt?
ANSWER: 10.5 g (formula = KI)
13. What is the pOH of a 0.0075M nitric acid (HNO3)solution?
pH = -log(0.0075)
= 2.1
pOH = 14 – pH
= 11.9
1 HNO3  1H+ + 1NO3Nitric acid is an acid and produces
H+ in solution…..remember?
[H+] = Macid
Formulas:
14. What is the pH of a 0.0010 M
solution of sodium hydroxide (NaOH)?
pH = -log[H+]
pOH = -log(0.0010)
pOH = -log[OH-]
[H+] = 10-pH
= 3.0 [OH-] = Mbase
[OH-] = 10-pOH
NaOH
is
a
base
and
produces
pH = 11
OH- in solution…remember?
1NaOH 1Na+ + 1OH-
pH + pOH = 14
15. What is the pH of a solution that contains
0.75 moles of hydrochloric acid (HCl) dissolved in
1.5 liters of water?
pH = -log[H+]
[H+] = [acid]
[acid] = M = 0.75 moles/1.5L
Formulas:
= 0.50M
pH = -log(0.50)
pH = -log[H+]
pOH = -log[OH-]
pH = 0.30
[H+] = 10-pH
[OH-] = 10-pOH
pH + pOH = 14
16. What is the pH of a solution that contains 5.6 grams of
sulfuric acid (H2SO4) dissolved in 650 ml water?
pH = -log[H+]
[H+] = [acid]
[acid] = M = moles/L
moles: 5.6 g H2SO4 (1 mole H2SO4 )
98.09 g H2SO4
= 0.057090 moles
Formulas:
Liters: 650 ml water  0.65 L
M = 0.057090 moles/ 0.65 L
pH = -log[H+]
pOH = -log[OH-]
= 0.0878307 M
+] = 10-pH
[H
pH = -log(0.0878307)
[OH-] = 10-pOH
= 1.1
pH + pOH = 14