Concentrations of solutions

2 marks · Normal

A solution contains 4.0 g of potassium chloride (KCl) dissolved in exactly 100 cm³ of water. Calculate the concentration of this solution in g/dm³.

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40 g/dm³ (±0.5)

Also accept: 40.0 g/dm³

Common mistakes: Not converting cm³ to dm³ (giving 4.0 g/dm³); Incorrectly dividing or multiplying

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Marking points

M1 · 1 mark · Converts 100 cm³ to 0.1 dm³ OR writes correct expression: concentration = mass/volume in dm³

A1 · 1 mark · Correct concentration in g/dm³ (40); allow 40.0; must include correct units

Worked solution

Volume in dm³ = 100 cm³ ÷ 1000 = 0.1 dm³