Chapter 6 Practice Paper: Maintaining Air Quality — question paper

Section A: Multiple-choice questions[10 marks]

Choose the one correct answer for each question.

1. 1

   The two most plentiful gases in clean, dry air are

   1. Aoxygen and carbon dioxide
   2. Bnitrogen and oxygen
   3. Coxygen and argon
   4. Dnitrogen and carbon dioxide
   ( )
2. 2

   Which pollutant is formed by the reaction of nitrogen and oxygen at very high temperatures?

   1. Asulfur dioxide
   2. Bcarbon monoxide
   3. Coxides of nitrogen
   4. Dmethane
   ( )
3. 3

   A weather station in volcanic countryside records high SO₂ without any human industry. The source is

   1. Alightning storms
   2. Bvolcanic emissions
   3. Crice paddies
   4. Docean spray
   ( )
4. 4

   Acid rain attacks limestone buildings fastest because limestone

   1. Acontains calcium carbonate, which reacts with acids
   2. Bis made of soluble sodium salts
   3. Cabsorbs sulfur dioxide irreversibly
   4. Dmelts in warm rain
   ( )
5. 5

   Burning forests in a clearing season add CO₂ while removing photosynthesis. The immediate effect on atmospheric CO₂ is that it

   1. Arises, as inputs increase and removals fall
   2. Bfalls, as removals increase
   3. Cstays exactly constant
   4. Dbecomes nitrogen
   ( )

Section B: Structured questions[20 marks]

Answer all questions in the spaces provided. Show all necessary working. Give numerical answers to 3 significant figures where appropriate, with units.

1. 1

   Clean, dry air is a mixture with a steady composition.

   1. (a)

      State the percentages of nitrogen and oxygen in clean, dry air.

      [1]
   2. (b)

      Calculate the volume of nitrogen and of oxygen in a 600 cm³ sample of clean, dry air.

      nitrogen = ...... cm³; oxygen =cm³[2]
   3. (c)

      Name the main gases making up the remaining volume.

      [1]
   4. (d)

      Explain why air is described as a mixture rather than a compound.

      [2]
2. 2

   Traffic, a coal-fired power station and a gas leak at a waste dump all contribute to a town's air problem.

   1. (a)

      Name the pollutant each source is most likely to add, and state the chemical reason for each.

      [3]
   2. (b)

      Explain why carbon monoxide from congested traffic is more dangerous in an enclosed underpass than in open air, and describe how it harms the body.

      [4]
3. 3

   Atmospheric carbon dioxide has been rising for decades.

   1. (a)

      Name the three carbon-cycle processes that determine atmospheric CO₂, and state for each whether it adds CO₂ to the air or removes it.

      [3]
   2. (b)

      Explain, using these processes, why cutting down large forest areas raises atmospheric CO₂ twice over.

      [2]
   3. (c)

      Name two greenhouse gases and state two consequences of their rising levels.

      [2]