Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
How the physical properties of hydrocarbons change with molecule size
19 practice questions
Practice questions
1–3 of 3 · Hard
Question 1
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 2
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 3
2 marks · Hard
Answer and see the solution →Explain why hydrocarbons with larger molecules are less useful as fuels than those with smaller molecules.