Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
How the physical properties of hydrocarbons change with molecule size
19 practice questions
Practice questions
1–10 of 19
Question 1
1 mark · Easy
Answer and see the solution →State one physical property that changes as the number of carbon atoms in a hydrocarbon increases.
Question 2
3 marks · Easy
Answer and see the solution →The table shows two hydrocarbon fractions obtained from crude oil.
(a)[1 mark]Hydrocarbon fractions Fraction Approx. number of carbon atoms Fuel gas 3 Lubricating oil 20 Which fraction is more viscous?
(b)[2 marks]Explain your answer to part (a).
Question 3
2 marks · Easy
Answer and see the solution →A scientist finds that a sample of kerosene starts to boil at 170 C, while a sample of diesel from the same crude oil boils at 280 C. Calculate the difference in boiling points between these two fractions.
Question 4
2 marks · Easy
Answer and see the solution →Explain why smaller hydrocarbons are used as fuels more often than larger hydrocarbons.
Question 5
3 marks · Easy
Answer and see the solution →The table shows information about three fractions from crude oil.
(a)[1 mark]Hydrocarbon fractions from crude oil Fraction Approx. number of carbon atoms Boiling point (°C) Petroleum gas 4 −1 Diesel 16 260 Bitumen 70 over 350 Which fraction is most volatile?
(b)[2 marks]Describe the relationship between the number of carbon atoms and boiling point for these fractions.
Question 6
1 mark · Easy
Answer and see the solution →State the colour of hydrocarbon fractions with the largest molecules.
Question 7
3 marks · Easy
Answer and see the solution →Fuel oil and gasoline (petrol) are both hydrocarbon fractions collected from crude oil.
(a)[1 mark]State which of the two fractions is expected to evaporate more quickly at room temperature.
(b)[2 marks]Give a reason for your answer to part (a).
Question 8
2 marks · Easy
Answer and see the solution →A sample of gasoline contains hydrocarbons with 8 carbon atoms per molecule. A sample of wax contains hydrocarbons with 30 carbon atoms per molecule. Calculate how many more carbon atoms per molecule are in wax than in gasoline.
Question 9
2 marks · Normal
Answer and see the solution →State how the boiling point and viscosity of hydrocarbons change as the length of their carbon chain increases.
Question 10
4 marks · Normal
Answer and see the solution →Crude oil is separated into fractions by fractional distillation. Each fraction contains hydrocarbons of different chain lengths.
(a)[2 marks]Name one fraction obtained from crude oil and state a common use for this fraction.
(b)[2 marks]Describe two ways in which the physical properties of the hydrocarbons in this fraction differ from those in the fraction with the largest molecules.