Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
141–150 of 335 · Normal
Question 141
2 marks · Normal
Answer and see the solution →State the general formula for alkenes. Write the molecular formula for the alkene with six carbon atoms.
Question 142
4 marks · Normal
Answer and see the solution →Ethene, propene and butene are alkenes.
(a)[3 marks]Complete the table to show the number of carbon (C) and hydrogen (H) atoms in each alkene.
Alkene Number of C atoms Number of H atoms Ethene 2 Propene Butene (b)[1 mark]State the physical state (solid, liquid or gas) of these alkenes at room temperature.
Question 143
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 144
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 145
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 146
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 147
2 marks · Normal
Answer and see the solution →State the general formula for alkenes and give the displayed formula for propene.
Question 148
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 149
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 150
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.