Chemistry Crossword

4. A chemical species formed when two elements join together?
7. A gas in an atmosphere that absorbs and emits radiation within the thermal infrared range?
9. A reaction that takes heat in?
10. Takes up 78% of the Earth's atmosphere?
12. Fuel, Heat and Oxygen?
15. The process of applying a protective zinc coating to steel or iron, in order to prevent rusting?
16. A reaction that gives off heat?

1. Formed by the reaction of iron and oxygen in the presence of water or air moisture?
2. Two or more atoms that have been chemically combined to form a single species?
3. The sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species?
5. Takes up 21% of the Earth's atmosphere?
6. Takes up 0.04% of the Earth's atmosphere?
8. Takes up 0.9% of the Earth's atmosphere?
11. Smallest stable particle?
13. An atom or molecule that has gained or lost one or more of its valence electrons?
14. A substance that contains only one type of atom?
17. Two or more substances which have been combined such that each substance retains its own chemical identity?