1. Solutions and Solubility
Solution Concentration

2. What is “Solution Concentration”?
Concentration = the quantity of a given solute in a solution
In general,
Concentration = quantity of solute
quantity of solution

3. Some Important Terms
Dilute = having a relatively small quantity of solute per unit volume of solution
Concentrated = having a relatively large quantity of solute per unit volume of solution

4. Concentration Units

5. % W/V (%m/v)
This concentration usually describes a solid solute dissolved in a liquid solvent.
Example of a solution that uses this concentration unit:
Intravenous solution is 0.90% (m/v) NaCl
(this means 0.90g NaCl dissolved in 100mL of solution)

6. Example 1
A box of apple juice has a fructose (sugar) concentration of 12 g/100 mL (12% W/V). What mass of fructose is present in a 175 mL glass of juice)?
volume of solution (apple juice) = 175 mL
% W/V = 12 %
mass of solute (fructose) = ?
%W/V = mass of solute X
volume of solution
mass of solute = % W/V X volume of solution
100
= 12 g/mL X mL
= 21 g

7. % W/W (%m/m)
This concentration usually describes a solid solute in a solid solvent.
Example of a solution that uses this concentration unit:
Toothpaste is
0.24% (m/m) SnF2
(this means 0.24g SnF2 dissolved in100g of solution)

8. Example 2
A sterling silver ring has a mass of 12.0 g and contains 11.1 g of pure silver. What is the percentage weight by weight concentration of silver in the metal?
mass of solute = 11.1 g
mass of solution = 12.0 g
% W/W = ?
% W/W = mass of solute X
mass of solution
= 11.1 g X 100
12.0 g
= 92.5 %

9. % V/V (%v/v)
This concentration usually describes a liquid solute in a liquid solvent.
Example of a solution that uses this concentration unit:
Wine is
11.0% (v/v) Ethanol (C2H5OH)
(this means 11.0 mL of ethanol is dissolved in 100mL of solution, ie the wine.)
% v/v = volume of solute x 100%
volume of solution

10. Example 3 % v/v = volume of ethanol X 100 volume of solution
Gasohol, which is a solution of ethanol and gasoline, is considered to be a cleaner fuel than just gasoline alone. A typical gasohol mixture available across Canada contains 4.1L of ethanol in a 55L tank of fuel. Calculate the percentage by volume concentration of ethanol.
% v/v = volume of ethanol X
volume of solution
= 4.1L X 100
55L
= 7.5%

11. parts per million - ppm
This concentration unit is for very small quantities of solute
c (ppm) = amount of solute
amount of solution
Example of a solution that uses this concentration unit:
Bottled water contains
280 ppm of HCO31-, 118 ppm Ca…
(this means every parts of solution contain 280 parts of HCO31- solute)
*1ppm = 1 drop of water in a bathtub

12. Units for ppm 1ppm = 1 mg/L 1 mg/kg 1 μg/g
*Choose the unit that matches the information given in the example you are calculating.

13. Example 4:
If the concentration of oxygen in water is 8 ppm, what mass of oxygen is present in 150 mL of water?
c = 8 ppm (mg/L)
v (volume of solution) = 150 mL = L
m (mass of oxygen) = ?
c = m v
m = c X v
m = 8 mg/L X L
m = 1 mg

14. Molar Concentration - Molarity (M)
This concentration unit describes the amount of solute (in moles) dissolved in 1 L of solution.
Example of a solution that uses this concentration unit:
Hydrochloric acid - HCl 1.25M (mol/L)
This means that 1.25 moles of HCl are dissolved in 1.00L of solution.
Chemists use Molarity because it allows them to relate concentration to moles of a substance.
Molar concentration = amount of solute (mol)
volume of solution (L)
C = n v

15. Example 5:
When 2.00 g of KMnO4 is dissolved into mL of solution, what molar concentration results?
m = 2.00 g
V = mL
C = ?
C = n V
n = m M
n = 2.00 g
158.04g/mol
= mol
C = mol L
= mol/L

16. Example 6:
How many grams of KMnO4 are needed to make mL of a mol/L solution?
C = mol/L
V = mL (0.5000L)
m = ?
C = n V
n = C X V
= mol/L X L
= mol
m = M X n
= g/mol X mol
= g