Coding for the type of compound
2 marks · EasyExplain how you can tell from its name that but-2-ene belongs to the alkene family and not the alkane family.
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The name ends with 'ene', which shows it is an alkene (contains a C=C double bond), not an alkane. 'Alkanes' have names ending in 'ane' and only single bonds, but-2-ene has a double bond at the second carbon.
Also accept: Names ending in 'ene' mean alkene, so but-2-ene is not an alkane.
Common mistakes: Thinking any four-carbon compound is an alkane; Not mentioning double bond
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Marking points
M1 · 1 mark · Recognises the 'ene' ending as indicating alkene family or a C=C double bond.
M2 · 1 mark · Distinguishes this from alkanes, which end with 'ane' and have only single carbon bonds.
Worked solution
The name 'but-2-ene' ends in 'ene', which is the ending for alkenes, not alkanes (which end in 'ane'). Also, 'ene' means there is a carbon–carbon double bond. Therefore, but-2-ene belongs to the alkene family.