Hydrocarbons and fossil fuelsIB MYP Sciences: Mind map

Exam questions on Hydrocarbons and fossil fuels

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.
   Explain why bitumen is collected at the bottom of the column.2 marks
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.
   Describe how coal was formed.2 marks
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.
   Describe the trend in Mei's results and explain it.3 marks