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6.3 Solution Concentration
What is “Solution Concentration”?
 Concentration = the quantity of a given solute in a solution
 In general,
Concentration = quantity of solute
quantity of solution
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
Concentration Units
1.


% 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)
Example 1
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2.
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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)?
% 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)
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?
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3.


6.3 Solution Concentration
% 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 is11.0% (v/v) Ethanol
(this means 11.0 mL of ethanol is dissolved in 100mL of solution, ie the wine.)
Example 3
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4.

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.
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 1 000 000 parts of solution contain 280 parts of HCO 31- solute)
*1ppm = 1 drop of water in a bathtub

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.

Example 4:
If the concentration of oxygen in water is 8 ppm, what mass of oxygen is present in 150
mL of water?
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5.
6.3 Solution Concentration
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.
Example 5:

When 2.00 g of KMnO4 is dissolved into 100.0 mL of solution, what molar concentration
results?
Example 6:

How many grams of KMnO4 are needed to make 500.0 mL of a 0.200 mol/L solution?