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What is the concentration of a solution?
Concentration
A solution is made
solute goes into solvent
↓
How much solute went in?
compared to the whole solution
↓
That amount is the concentration of the solution
- The concentration tells us how much solute is dissolved in a given amount of solvent or solution.
- The right proportion is always essential when preparing a solution.
- Concentration matters not just in the laboratory but in medicine, farming, food, cosmetics — even in making a cup of tea.
Definition
The amount of solute dissolved in a given amount of solvent or solution is termed the concentration of the solution .
Example 5.1 — 10 g of salt is dissolved in 90 g of water. Find the mass by mass percentage.
What is given
- Solute is salt , mass = 10 g
- Solvent is water , mass = 90 g
- Solution is salt + water, mass = 10 g + 90 g = 100 g
Calculation
Mass by mass percentage
=
Mass of solute
Mass of solution
× 100
=
10 g
100 g
× 100 =
10 % m/m
- m/m means mass divided by mass.
Do we always take mass by mass?
- No. Sometimes weighing a liquid is difficult but measuring its volume is easy.
- So concentration can also be expressed using volume. Let us see how.
