Hydrocarbons and fossil fuelsIB MYP Sciences: Subtopic test

1. 1
   At an oil refinery in Rotterdam, crude oil is heated until it vaporises and the vapour is fed into a tall fractionating column. The column is very hot at the bottom and much cooler at the top. Crude oil is a mixture of hydrocarbons, and different groups of hydrocarbons, called fractions, are collected at different heights in the column.

   (a)

   Which property of hydrocarbons allows them to be separated in the fractionating column?

   [1 mark]

   • ATheir colour
   • BTheir solubility in water
   • CTheir electrical conductivity
   • DTheir different boiling points

   (b)

   Which fraction would be collected nearest to the top of the column?

   [1 mark]

   • ABitumen
   • BRefinery gases
   • CDiesel
   • DFuel oil

   (c)

   Explain why bitumen is collected at the bottom of the column.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A museum exhibit in Aberdeen explains how fossil fuels formed millions of years ago. It displays a fossilised fern from a coal seam beside a model of an offshore oil platform, and notes that natural gas contains alkanes such as methane, ethane and propane.

   (a)

   How was crude oil formed?

   [1 mark]

   • AFrom the remains of tiny sea organisms that were buried and exposed to heat and pressure for millions of years
   • BFrom dead land plants in swamps that were compressed to form solid rock
   • CFrom volcanic rock that melted deep underground
   • DFrom waste from modern farms that was stored for a few years

   (b)

   Which of these is the correct formula for propane?

   [1 mark]

   • ACH₄
   • BC₂H₆
   • CC₃H₈
   • DC₄H₁₀

   (c)

   Describe how coal was formed.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   Mei, a student in Seoul, investigates how acid rain affects limestone buildings. She places identical marble chips (calcium carbonate) of the same mass in beakers containing the same volume of solutions with different pH values for 24 hours, then dries and reweighs them. The mass lost was 0.9 g at pH 2, 0.4 g at pH 4, 0.1 g at pH 6 and 0.0 g at pH 7. She did each test once.

   (a)

   Describe the trend in Mei's results and explain it.

   [3 marks]

   (b)

   Evaluate how well Mei's investigation models the effect of acid rain on a limestone building, and suggest two improvements.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A city in northern India relies on a coal-fired power station and large numbers of diesel vehicles. In winter, residents report a thick haze and more breathing problems, and the surface of a 400-year-old marble monument is being eaten away. The city council wants to understand which pollutants come from burning these fuels, what harm they do, and what could be done about them.

   (a)

   Explain how burning fossil fuels produces pollutants and how each pollutant causes harm. Include carbon dioxide, sulfur dioxide, nitrogen oxides and particulates.

   [6 marks]

   (b)

   Discuss and evaluate whether the council should ban diesel vehicles from the city centre.

   [6 marks]

   Total for question 4: 12 marks

End of questions