Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Chapter
Alkenes
106 practice questions
Topics covered
Practice questions
11–20 of 44 · Normal
Question 11
3 marks · Normal
Answer and see the solution →An alkene molecule contains 14 hydrogen atoms. Calculate the number of carbon atoms it contains. Show your working.
Question 12
3 marks · Normal
Answer and see the solution →Hexene (C6H12) and butene (C4H8) are both alkenes. Explain why hexene has a higher boiling point than butene, referring to their structure and trends among alkenes (C2–C4).
Question 13
4 marks · Normal
Answer and see the solution →The table below shows the number of carbon atoms and the molecular formula for three alkenes. For each, state if the formula is correct for an alkene. If not, explain your answer.
Alkene Number of C atoms Molecular formula W 4 C4H8 X 5 C5H12 Y 3 C3H6 Question 14
1 mark · Normal
Answer and check →Which statement about the physical properties of alkenes with 2 to 4 carbon atoms is correct?
- A.They are all gases at room temperature.
- B.They are all liquids at room temperature.
- C.Their boiling points decrease as the number of carbon atoms increases.
- D.They are solids at room temperature.
Question 15
2 marks · Normal
Answer and see the solution →State the general formula for alkenes and give the displayed formula for propene.
Question 16
4 marks · Normal
Answer and see the solution →The table below gives information about three alkenes.
Alkene Number of carbon atoms Boiling point (°C) Ethene 2 -104 Propene 3 -47 Butene 4 -6 (a)[2 marks]Describe the trend in boiling points shown in the table.
(b)[2 marks]Explain why the boiling point increases as the number of carbon atoms increases.
Question 17
2 marks · Normal
Answer and see the solution →State the type of chemical reaction that occurs when ethene reacts completely with oxygen. Write the names of the two products formed in this reaction.
Question 18
4 marks · Normal
Answer and see the solution →Butene (C4H8) is an alkene that can undergo combustion and addition reactions.
(a)[2 marks]Write the balanced chemical equation for the complete combustion of butene (C4H8) in oxygen.
(b)[2 marks]Describe what happens to the C=C double bond when butene reacts with bromine, Br2.
Question 19
3 marks · Normal
Answer and see the solution →An alkene has 8 carbon atoms in its molecule.
Calculate the number of hydrogen atoms present in one molecule of this alkene. Show your working.
Question 20
3 marks · Normal
Answer and see the solution →Alkenes are described as unsaturated hydrocarbons.
Explain what 'unsaturated' means and how you can test for unsaturation using a chemical reaction.