Structural isomerism and E-Z isomerismAQA A-Level Chemistry: Mind map

Exam questions on Structural isomerism and E-Z isomerism

1. A refinery chemist is analysing the C₅ fraction of a petroleum sample. The fraction is a mixture of alkanes with the molecular formula C₅H₁₂, which are blended into petrol.
   Explain why pentane and 2-methylbutane are structural isomers of each other.2 marks
2. A student is comparing four alkenes: but-1-ene, CH₂=CHCH₂CH₃; but-2-ene, CH₃CH=CHCH₃; 2-methylpropene, (CH₃)₂C=CH₂; and propene, CH₃CH=CH₂.
   In one isomer of but-2-ene, both methyl groups are on the same side of the double bond. Use the CIP priority rules to explain why this isomer is the Z isomer.2 marks
3. But-1-ene, CH₂=CHCH₂CH₃, is an alkene used to make polymers. Its molecular formula, C₄H₈, is shared by several other compounds.
   Explain why but-1-ene does not show E-Z isomerism but but-2-ene does.3 marks