Pearson Edexcel International GCSE (9–1) · CHEMISTRY · Unit
Organic Chemistry
785 practice questions
Topics covered
Practice questions
51–60 of 133 · Hard
Question 51
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 52
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.
Question 53
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 54
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 55
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.
Question 56
2 marks · Hard
Answer and see the solution →A student claims that all alkenes have the same general formula. State this general formula and explain how it shows that alkenes are unsaturated.
Question 57
5 marks · Hard
Answer and see the solution →The physical properties of alkenes with 2 to 4 carbon atoms show a trend.
(a)[2 marks]State the physical state of ethene, propene and butene at room temperature.
(b)[2 marks]Describe how the boiling points of these alkenes change as the number of carbon atoms increases from ethene to butene.
(c)[1 mark]Explain why the trend you described in part (b) occurs.
Question 58
2 marks · Hard
Answer and see the solution →State the general formula for alkenes. Explain, using your formula, how you can determine the number of hydrogen atoms in an alkene containing 9 carbon atoms.
Question 59
2 marks · Hard
Answer and see the solution →State the products formed when pentene (C5H10) undergoes complete combustion in oxygen. Write a balanced chemical equation for the reaction.
Question 60
5 marks · Hard
Answer and see the solution →This question is about reactions of hexene (C6H12).
(a)[2 marks]Describe what happens to the C=C double bond in an addition reaction of hexene.
(b)[2 marks]State the product formed when hexene reacts with hydrogen in an addition reaction. Suggest the molecular formula of the product.
(c)[1 mark]Write a chemical equation for the complete combustion of hexene.