Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Section
Unsaturated hydrocarbons
19 practice questions
Practice questions
11–19 of 19
Question 11
3 marks · Normal
Answer and see the solution →A straight-chain alkene contains 7 carbon atoms. Calculate:
(a)[1 mark]Write the molecular formula of this alkene.
(b)[2 marks]Calculate the total number of hydrogen atoms in 5 molecules of this alkene.
Question 12
3 marks · Normal
Answer and see the solution →An unknown hydrocarbon has the molecular formula C3H6.
Explain why this compound must be an alkene rather than an alkane.
Question 13
4 marks · Normal
Answer and see the solution →The table below shows the number of carbon and hydrogen atoms in three different hydrocarbons.
Hydrocarbon Data Compound Number of carbon atoms Number of hydrogen atoms W 4 10 X 5 12 Y 6 12 (a)[2 marks]Which compound(s) could be an alkene? Explain your answer using the general formula.
(b)[2 marks]For any one compound that is not an alkene, state what structural feature it likely has instead.
Question 14
1 mark · Normal
Answer and check →Which of the following is a possible isomer of butene (C4H8)?
- A.CH3CH2CH=CH2
- B.CH3CH=CHCH3
- C.CH2=C(CH3)2
- D.All of the above
Question 15
2 marks · Normal
Answer and see the solution →Draw the displayed formula of ethene. Name the type of bond that makes ethene an unsaturated hydrocarbon.
Question 16
4 marks · Normal
Answer and see the solution →Alkenes are described as unsaturated because of a feature of their structure.
(a)[2 marks]Describe the bonding in an unsaturated hydrocarbon.
(b)[2 marks]Explain how a C=C bond affects the reactivity of alkenes compared to alkanes.
Question 17
2 marks · Hard
Answer and see the solution →Explain why alkenes are classified as unsaturated hydrocarbons and describe the significance of the C=C bond in their chemical reactivity.
Question 18
5 marks · Hard
Answer and see the solution →Butene ( C4H8 ) has several isomers.
(a)[2 marks]Draw the displayed formula of the branched-chain isomer of butene.
(b)[1 mark]Draw the displayed formula of one straight-chain isomer of butene where the double bond is at the end of the carbon chain.
(c)[2 marks]Explain why these structures are isomers of each other.
Question 19
2 marks · Hard
Answer and see the solution →State the name and draw the displayed formula of the alkene that has four carbon atoms in a continuous chain with the double bond between the second and third carbon atoms.