Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Alkanes
18 practice questions
Practice questions
11–18 of 18
Question 11
3 marks · Normal
Answer and see the solution →Explain why alkanes have the general formula CnH2n+2, making reference to the bonding and structure of these molecules.
Question 12
4 marks · Normal
Answer and see the solution →The table below shows the number of carbon and hydrogen atoms in three different unbranched alkanes.
Alkane Number of carbon atoms Number of hydrogen atoms Methane 1 4 Butane 4 10 Nonane 9 20 (a)[2 marks]Using the data, deduce the general formula connecting the number of hydrogen atoms (H) to the number of carbon atoms (C) in alkanes.
(b)[1 mark]Predict the number of hydrogen atoms in a straight-chain alkane with 7 carbon atoms.
(c)[1 mark]Name the alkane with 9 carbon atoms.
Question 13
1 mark · Normal
Answer and check →What is required for a substitution reaction between ethane and chlorine to take place?
- A.High pressure
- B.A catalyst
- C.Ultraviolet light
- D.Heating to 1000°C
Question 14
2 marks · Normal
Answer and see the solution →What are the two elements found in all alkanes? State why alkanes are described as saturated.
Question 15
4 marks · Normal
Answer and see the solution →Draw and name the displayed formulae for the following straight-chain alkanes.
(a)[2 marks]An alkane with four carbon atoms.
(b)[2 marks]An alkane with five carbon atoms.
Question 16
2 marks · Hard
Answer and see the solution →The molecular formula for an alkane with 16 carbon atoms is C₁₆H₃₄. State the general formula for alkanes. Using this formula, explain how you can determine the number of hydrogen atoms in any unbranched alkane.
Question 17
5 marks · Hard
Answer and see the solution →This question is about unbranched alkanes.
(a)[2 marks]Draw the displayed (structural) formula of the straight-chain alkane with eight carbon atoms.
(b)[1 mark]Write the name of this alkane.
(c)[1 mark]State the molecular formula for this compound.
(d)[1 mark]How many single carbon–carbon bonds are present in one unbranched molecule of this alkane? Show your reasoning.
Question 18
2 marks · Hard
Answer and see the solution →Butane reacts with bromine in the presence of ultraviolet light. Write a balanced chemical equation for the mono-substitution reaction of butane with bromine. Name the type of reaction and describe briefly what happens during this reaction.