Air pollutionIB MYP Chemistry: Subtopic test

1. 1
   An air-quality monitoring station beside a busy road in Mexico City records high levels of carbon monoxide, nitrogen oxides and particulates at rush hour. Most of the vehicles on the road use petrol or diesel engines.

   (a)

   How are nitrogen oxides formed in a vehicle engine?

   [1 mark]

   • ANitrogen and oxygen from the air react at the high temperature in the engine
   • BThe fuel contains large amounts of nitrogen, which burns
   • CCarbon monoxide reacts with nitrogen in the exhaust pipe
   • DNitrogen reacts with the water vapour in the exhaust

   (b)

   Which pollutant consists of tiny solid particles, such as unburnt carbon, from diesel engines?

   [1 mark]

   • ACarbon monoxide
   • BSulfur dioxide
   • CParticulates
   • DNitrogen oxides

   (c)

   Describe two harmful effects of nitrogen oxides.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A student in Seoul compares particulate pollution at four sites. At each site she fixes a clean microscope slide, coated in a thin layer of petroleum jelly, to a post 1.5 m above the ground and leaves it for seven days. She then counts the dark particles stuck to a 1 cm² area of each slide. The counts are: roadside 48, school playground 20, park 9 and a hill 3 km from any road 6.

   (a)

   Which is the independent variable in this investigation?

   [1 mark]

   • AThe number of particles on the slide
   • BThe location of the slide
   • CThe height of the slide above the ground
   • DThe length of time the slide is left out

   (b)

   Which change would make the results more reliable?

   [1 mark]

   • AUsing a different type of jelly at each site
   • BLeaving the slides for different times at different sites
   • CCounting only the square with the most particles
   • DUsing several slides at each site and calculating a mean

   (c)

   Describe the pattern in the results and suggest a reason for it.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   In many countries new petrol cars must be fitted with a catalytic converter. This is a metal honeycomb coated with platinum and rhodium, which the hot exhaust gases pass through before leaving the car.

   (a)

   Write a word equation for the reaction in a catalytic converter that changes carbon monoxide and nitrogen monoxide into less harmful gases, and explain why the products are less harmful.

   [3 marks]

   (b)

   A catalytic converter does not stop climate change. Explain why not, and describe one other way to reduce air pollution from road transport.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Most of the electricity in a country in southern Africa comes from coal-fired power stations, which release sulfur dioxide and cause acid rain over nearby farmland and forests. The government is considering a law to fit every power station with equipment that removes sulfur dioxide from the chimney gases by reacting it with calcium carbonate. The equipment is expensive and would raise electricity prices.

   (a)

   Discuss the benefits and drawbacks of making every power station fit this equipment, and reach a justified conclusion.

   [6 marks]

   (b)

   Explain how burning coal leads to acid rain, and describe two effects of acid rain.

   [6 marks]

   Total for question 4: 12 marks

End of questions