Choose from the gases to answer the questions. argon carbon dioxide carbon monoxide ethane hydrogen methane neon ozone sulfur dioxide sulfur trioxide Each gas can be used once, more than once or not at all. Which gas:

1. (a)is used to manufacture margarine[1]
2. (b)is used as a food preservative[1]
3. (c)has a molecule that contains only eight atoms[1]
4. (d)is formed from bacterial decay of vegetable matter[1]
5. (e)is formed in photochemical smog[1]
6. (f)completely combusts to form only a gas that turns limewater milky?[1]