<Tr> <Td> Metals </Td> <Td> <0.1% </Td> </Tr> <P> Four different types of hydrocarbon molecules appear in crude oil . The relative percentage of each varies from oil to oil, determining the properties of each oil . </P> <Table> Composition by weight <Tr> <Th> Hydrocarbon </Th> <Th> Average </Th> <Th> Range </Th> </Tr> <Tr> <Td> Alkanes (paraffins) </Td> <Td> 30% </Td> <Td> 15 to 60% </Td> </Tr> <Tr> <Td> Naphthenes </Td> <Td> 49% </Td> <Td> 30 to 60% </Td> </Tr> <Tr> <Td> Aromatics </Td> <Td> 15% </Td> <Td> 3 to 30% </Td> </Tr> <Tr> <Td> Asphaltics </Td> <Td> 6% </Td> <Td> remainder </Td> </Tr> </Table> <Tr> <Th> Hydrocarbon </Th> <Th> Average </Th> <Th> Range </Th> </Tr>

What are the various hydrocarbons present in crude oil