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Chapter 16 Practice Paper: Chemical analysis — question paper

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GCSE (9–1) · GCSE Chemistry (Foundation and Higher)

Chapter 16 Practice Paper

Chemical analysis

Duration: 40 minutes
Total: 30 marks
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Class:
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READ THESE INSTRUCTIONS FIRST

  • Answer all questions.
  • Section A contains ten multiple-choice questions. Choose one answer, A, B, C or D, for each.
  • Section B contains structured questions. Write your answers in the spaces provided.
  • The number of marks is given in brackets [ ] at the end of each question or part question.
  • The total mark for this paper is 30.

Original practice material written for the MOE GCSE Chemistry syllabus. It is not an official MOE or school examination paper. Chapter 16: purity and formulations, paper chromatography and Rf, the four gas tests, and (Chemistry only) flame tests, metal-ion and anion tests, and instrumental methods.

For Examiner’s Use
Section A/ 10
Section B/ 20
Total/ 30

Section A: Multiple-choice questions[10 marks]

Choose one answer for each question. Each question is worth 1 mark.

  1. 1

    A pure substance boils

    1. Aover a wide range of temperatures
    2. Bonly in the presence of a catalyst
    3. Cat gradually changing temperatures
    4. Dat one fixed temperature
    ( )
  2. 2

    A spot moves 3.0 cm while the solvent front moves 5.0 cm. The Rf value is

    1. A0.6
    2. B1.7
    3. C15
    4. D8
    ( )
  3. 3

    The gas that burns with a squeaky pop is

    1. Aoxygen
    2. Bcarbon dioxide
    3. Chydrogen
    4. Dchlorine
    ( )
  4. 4

    (Chemistry only) The flame colour of lithium ions is

    1. Ayellow
    2. Bcrimson
    3. Cgreen
    4. Dlilac
    ( )
  5. 5

    (Chemistry only) Iron(II) ions with NaOH solution give a precipitate coloured

    1. Ablue
    2. Bbrown
    3. Cwhite
    4. Dgreen
    ( )
  6. 6

    (Chemistry only) The reagent that identifies halide ions is

    1. Asodium hydroxide
    2. Bsilver nitrate
    3. Cbarium chloride
    4. Dlimewater
    ( )
  7. 7

    (Chemistry only) Silver iodide is precipitated as a solid coloured

    1. Ayellow
    2. Bwhite
    3. Ccream
    4. Dblue
    ( )
  8. 8

    (Chemistry only) Flame emission spectroscopy is used to identify

    1. Aanions in solution
    2. Borganic dyes
    3. Cmetal ions
    4. Dgases only
    ( )
  9. 9

    A developed chromatogram shows a food colouring as three separate spots. This proves the colouring

    1. Ais a single pure dye
    2. Bcontains three components
    3. Cis insoluble in the solvent
    4. Dhas an Rf of exactly 3
    ( )
  10. 10

    The best way to show a colourless liquid is pure water is to measure its

    1. Acolour
    2. Btransparency
    3. Cvolume
    4. Dboiling point
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided.

  1. 11

    A student chromatographs an ink sample.

    1. (a)

      Explain why the baseline is drawn in pencil, not pen.

      [2]
    2. (b)

      State why the solvent must start below the baseline.

      [1]
    3. (c)

      The chromatogram shows one spot. State what this suggests about the ink.

      [1]
  2. 12

    A dye travels 2.4 cm while the solvent front travels 4.0 cm. Reference dyes: X has Rf 0.60, Y has Rf 0.75, Z has Rf 0.45.

    Chromatography data

    QuantityDistance
    Dye spot2.4 cm
    Solvent front4.0 cm
    1. (a)

      Calculate the Rf value of the dye.

      [2]
    2. (b)

      Identify the dye from the references.

      [1]
    3. (c)

      Explain why the reference dyes are run on the same chromatogram.

      [2]
    4. (d)

      Describe how the chromatogram would show that a colouring is a pure single dye.

      [3]
  3. 13

    (Chemistry only) An unknown colourless solution is analysed with three tests.

    1. (a)

      Dilute hydrochloric acid makes the solution fizz, and the gas clouds limewater. Name the anion and write the equation for the limewater change.

      [3]
    2. (b)

      A fresh sample with HCl then barium chloride gives a white precipitate. Name the anion.

      [1]
    3. (c)

      NaOH solution gives a blue precipitate. Name the cation and the equation for its formation.

      [3]
    4. (d)

      State one reason a water company would use an instrumental method instead of these manual tests.

      [1]

— End of paper —