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Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section

Concentrations of solutions

19 practice questions

Start practising (8 questions)

Practice questions

1–8 of 8 · Normal

  1. Question 1

    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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  2. Question 2

    4 marks · Normal

    (a)

    Give the formula that links concentration in mol/dm³, amount in mol, and volume in dm³.

    [1 mark]
    (b)

    A student dissolves 2.5 g of magnesium sulfate (MgSO₄, Ar: Mg = 24, S = 32, O = 16) in 200 cm³ of water.

    i. Calculate the number of moles of MgSO₄ in the solution.

    [1 mark]
    (c)

    ii. Calculate the concentration of MgSO₄ in mol/dm³ in the solution.

    [2 marks]
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  3. Question 3

    3 marks · Normal

    Calculate the mass of sodium nitrate (NaNO₃, Ar: Na = 23, N = 14, O = 16) required to make 250 cm³ of a 0.050 mol/dm³ solution.

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  4. Question 4

    3 marks · Normal

    A teacher claims that doubling the amount of solute added to a fixed volume of water will always double the concentration of the solution. Explain using calculations and an example whether this statement is correct.

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  5. Question 5

    4 marks · Normal

    Concentration and volume data for sodium sulfate solutions
    SampleConcentration (mol/dm³)Volume used (dm³)
    A0.100.020
    B0.200.015
    C0.400.025
    (a)

    Which sample contains the largest amount of sodium sulfate? Show your calculations.

    [2 marks]
    (b)

    State the amount in mol present in that sample.

    [1 mark]
    (c)

    Suggest one reason why a higher concentration solution may have less sodium sulfate than a lower concentration solution.

    [1 mark]
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  6. Question 6

    1 mark · Normal

    Which calculation gives the concentration, in mol/dm³, of a solution containing 1.5 mol of solute in 0.75 dm³ of solution?

    1. A.1.5 ÷ 0.75
    2. B.0.75 ÷ 1.5
    3. C.1.5 × 0.75
    4. D.0.75 × 1.5
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  7. Question 7

    2 marks · Normal

    Calculate the concentration in mol/dm³ of a solution containing 5.60 g of potassium hydroxide (KOH, Ar: K = 39, O = 16, H = 1) in 500 cm³ of solution.

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  8. Question 8

    4 marks · Normal

    (a)

    A solution has a concentration of 1.5 mol/dm³. What is the amount (in mol) of solute in 750 cm³ of this solution?

    [2 marks]
    (b)

    Describe how you would prepare 750 cm³ of this solution from a 3.0 mol/dm³ solution.

    [2 marks]
    Answer and see the solution →