How the physical properties of hydrocarbons change with molecule size
2 marks · EasyExplain why smaller hydrocarbons are used as fuels more often than larger hydrocarbons.
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Must show: Smaller hydrocarbons burn more easily, Smaller hydrocarbons are more volatile (evaporate more easily)
Also accept: Smaller hydrocarbons have lower boiling points, so they can vaporise and ignite easily
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Marking points
M1 · 1 mark · Recognises that smaller hydrocarbons burn more easily than larger hydrocarbons.
A1 · 1 mark · States that smaller hydrocarbons are more volatile or evaporate more easily.
Worked solution
Smaller hydrocarbons burn more easily because they are more volatile than larger hydrocarbons. This makes them more useful as fuels.