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Chapter 8 Practice Paper: Maintaining Air Quality — question paper

QuizQuipPractice Series
QQ/S4CH/CH8

Secondary 4 · Chemistry (G2 / G3)

Chapter 8 Practice Paper

Maintaining Air Quality

Duration: 40 minutes
Total: 30 marks
Name:
Class:
Register No.:
Date:

READ THESE INSTRUCTIONS FIRST

  • Write your name, class and register number in the spaces at the top of this page.
  • Answer all questions.
  • Give numerical answers correct to 3 significant figures unless stated otherwise, with units where a quantity is calculated.
  • Chemical equations should be balanced, with state symbols shown where the question asks for them.
  • The number of marks is given in brackets [ ] at the end of each question or part question.
  • The total number of marks for this paper is shown on its cover.

Original practice material written for the MOE Chemistry syllabus. It is not an official MOE or school examination paper. Chapter 8 (air composition, pollutants, acid rain, greenhouse effect, catalytic converters).

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

Section A: Multiple-choice questions[10 marks]

Choose the one correct answer for each question.

  1. 1

    Which gas makes up about 78% of clean, dry air?

    1. Aoxygen
    2. Bcarbon dioxide
    3. Cnitrogen
    4. Dargon
    ( )
  2. 2

    A poisoned victim of a runaway heater is found with bright-red skin. The gas responsible is

    1. Acarbon dioxide
    2. Bsulfur dioxide
    3. Ccarbon monoxide
    4. Dnitrogen dioxide
    ( )
  3. 3

    Which pollutant is reduced by flue-gas desulfurisation with limestone?

    1. Asulfur dioxide
    2. Bcarbon monoxide
    3. Cunburnt hydrocarbons
    4. Dozone
    ( )
  4. 4

    In the hot cylinder of a car engine, nitrogen and oxygen combine to form

    1. Anitrogen dioxide only
    2. Bnitrogen monoxide
    3. Cammonia
    4. Dnitric acid
    ( )
  5. 5

    A catalytic converter converts nitrogen oxides and carbon monoxide into

    1. Aammonia and oxygen
    2. Bnitrogen and carbon dioxide
    3. Cnitric acid and water
    4. Dozone and soot
    ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Include state symbols where the question asks, and balance every equation.

  1. 1

    60 cm³ of air is passed repeatedly over heated excess copper until the gas volume stops changing. The final reading is 47 cm³.

    1. (a)

      Write the equation for the reaction removing the oxygen.

      [1]
    2. (b)

      Calculate the volume of oxygen removed and the percentage of oxygen in the air sample.

      [3]
    3. (c)

      State the main gas remaining in the syringe and explain why it did not react.

      [1]
  2. 2

    Two coal-fired power stations supply the same city. Station P burns coal directly; station Q burns the same coal but sprays its flue gas with limestone slurry first.

    1. (a)

      Explain why the coal produces sulfur dioxide.

      [2]
    2. (b)

      Write the equation for the scrubber reaction and state why it reduces acid rain.

      [2]
    3. (c)

      State one environmental problem the scrubber does NOT solve.

      [2]
  3. 3

    A student claims: "Carbon dioxide is a natural part of the air and is needed by plants, so rising carbon dioxide levels are harmless."

    1. (a)

      State one natural process that removes CO₂ from the air and one that returns it.

      [2]
    2. (b)

      Explain the flaw in the student's argument, using the idea of the greenhouse effect.

      [3]
  4. 4

    City X records high levels of nitrogen oxides and unburnt hydrocarbons on sunny afternoons; city Y records high sulfur dioxide all year round.

    1. (a)

      State which city more likely has acid-rain damage to limestone buildings, and name the acid responsible.

      [2]
    2. (b)

      State which city more likely suffers summer photochemical smog, and name the two ingredients.

      [2]

— End of paper —