| A | B |
|---|
| natural resources formed from the ancient remains of microscopic animals and plants | natural gas and crude oil |
| not being made any more | finite |
| methane | CH4 |
| ethane | C2H6 |
| propane | C3H8 |
| butane | C4H10 |
| crude oil is | a liquid at room temperature |
| a mixture of hydrocarbons in a gas state | natural gas |
| petrochemicals are made | from crude oil |
| natural gas | is used for domestic heating |
| used as a fuel for aircraft | kerosene |
| used for surfacing roads and roofs | bitumen |
| viscous | thick |
| methane + oxygen | = carbon dioxide + water |
| carries oxygen | haemoglobin |
| carbon monoxide | CO |
| carbon dioxide | CO2 |
| carbon trioxide | CO3 |
| nitrogen dioxide | NO2 |
| carbon dioxide is | a greenhouse gas |
| cracking produces | hydrocarbons with double bonds |
| hydrocarbons with double bonds | alkenes |
