Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Crude Oil
106 practice questions
Topics covered
Practice questions
31–40 of 106
Question 31
3 marks · Normal
Answer and see the solution →Explain why hydrocarbons with larger molecules burn less easily than hydrocarbons with smaller molecules.
Question 32
4 marks · Normal
Answer and see the solution →The table below shows properties of different hydrocarbon fractions obtained from crude oil.
Properties of hydrocarbon fractions Fraction Approx. number of C atoms Boiling point (°C) Colour Flow (viscosity) Ease of burning Refinery gas 3 -20 Colourless Very runny Burns very easily Kerosene 12 200 Light yellow Fairly runny Burns easily Fuel oil 20 340 Dark brown Thick Does not burn easily (a)[2 marks]Which fraction is the most viscous? Give a reason for your answer.
(b)[2 marks]State how boiling point, colour, and ease of burning change as you go from refinery gas to fuel oil.
Question 33
1 mark · Normal
Answer and check →Which statement about hydrocarbon fractions with small molecules is correct?
- A.They have high boiling points and are very viscous.
- B.They are dark in colour and burn with difficulty.
- C.They are very volatile and burn easily.
- D.They are thick liquids and flow slowly.
Question 34
2 marks · Normal
Answer and see the solution →State two ways in which refinery gas differs in physical properties from bitumen, another fraction from crude oil.
Question 35
4 marks · Normal
Answer and see the solution →Hydrocarbon fractions are collected at different heights in a fractionating column, depending on their boiling points.
(a)[1 mark]State what is meant by the volatility of a liquid.
(b)[2 marks]Explain why the fraction collected at the top of the column is more volatile than the one at the bottom.
(c)[1 mark]Give one use each for the top fraction and the bottom fraction.
Question 36
2 marks · Hard
Answer and see the solution →State two changes in the physical properties of hydrocarbon fractions as the number of carbon atoms in their molecules increases.
Question 37
5 marks · Hard
Answer and see the solution →Crude oil is separated into fractions by fractional distillation. Two fractions, A and B, are collected at different heights in the fractionating column.
(a)[2 marks]Fraction A consists of large hydrocarbon molecules, while fraction B consists of small hydrocarbon molecules. State which fraction is collected higher up the column. Give a reason for your answer.
(b)[2 marks]Describe how the physical properties (boiling point and viscosity) of fraction A compare to those of fraction B.
(c)[1 mark]Suggest one use for fraction B, based on its physical properties.
Question 38
2 marks · Hard
Answer and see the solution →Explain why hydrocarbons with larger molecules are less useful as fuels than those with smaller molecules.
Question 39
1 mark · Easy
Answer and see the solution →State the name of the process used to separate crude oil into fractions based on their different boiling points.
Question 40
3 marks · Easy
Answer and see the solution →Methane is a hydrocarbon fuel. Answer the following questions about its combustion.
(a)[1 mark]Write a word equation for the complete combustion of methane.
(b)[1 mark]Give the names of the two products formed in this reaction.
(c)[1 mark]Explain why methane releases energy when it burns completely in air.