AP Chemistry · Topic 3.8

Representations of Solutions Practice

Part of Properties of Substances and Mixtures.(SPQ-3.B)

Practice questions

15

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Sample questions

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  1. Sample 1difficulty 1/5

    250 mL 0.025 mol NaCl

    The molarity of the solution is:

    • A

      0.025 M

    • B

      0.10 M

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    • C

      1.0 M

    • D

      0.25 M

    Why

    M = mol/L = 0.025 mol / 0.250 L = 0.10 M.

  2. Sample 2difficulty 2/5

    "5 ppm of lead" in water means

    • A

      5% by mass

    • B

      5 mol per liter

    • C

      5 mg of lead per liter (or 5 µg per gram)

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    • D

      5 g of lead per liter

    Why

    ppm = parts per million. For dilute aqueous solutions: 1 ppm ≈ 1 mg/L.

  3. Sample 3difficulty 2/5

    What is the molarity of a solution made by dissolving 0.5 mol of NaCl in 250 mL of water?

    • A

      1.0 M

    • B

      0.125 M

    • C

      0.5 M

    • D

      2.0 M

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    Why

    M = 0.5 / 0.250 = 2.0 mol/L.

  4. Sample 4difficulty 2/5

    100 mL of 0.10 M HCl is diluted to a final volume of 500 mL.

    0.10 M HCl 100 mL ? M HCl 500 mL

    The new molarity is:

    • A

      0.10 M

    • B

      0.50 M

    • C

      0.020 M

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    • D

      0.0050 M

    Why

    M1V1 = M2V2; (0.10)(100) = M2(500), giving M2 = 0.020 M.

  5. Sample 5difficulty 2/5

    The dilution equation is

    • A

      M₁ = M₂

    • B

      n₁ + n₂ = M

    • C

      M₁V₁ = M₂V₂

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    • D

      V₁ = V₂

    Why

    The number of moles of solute is conserved during dilution: n = M × V is constant.