CHEMISTRY REVIEW

2. – The process of coating metal, usually steel or iron, with a layer of zinc to prevent rusting.
4. Composition Reactions – Reactions where two or more substances combine to form one new compound.
5. - A metal used to protect iron rusting.
7. – The substances formed as a result of a chemical reaction.
11. Reaction – A process where substances change into new substances with different properties.
13. – A chemical used to kill or control unwanted plants (weeds).
14. – A substance that has a pH above 7 and produces hydroxide ions (OH⁻) in water.
19. – A reaction that absorbs heat energy.
20. – A solid that forms from a chemical reaction in a solution.
21. Reaction – A chemical reaction where a substance burns in oxygen, releasing heat and light.

1. Change – A change in a substance’s form or appearance without altering its chemical composition.
3. – A type of pesticide specifically used to kill insects.
4. Dioxide - A gas responsible for acid rain, along with Nitrogen Oxides.
6. – A method used to remove pollutants from industrial exhaust gases using liquid sprays or filters.
7. – A large molecule made of repeating smaller units called monomers.
8. Material – A man-made substance created through chemical processes.
9. Reaction – A chemical reaction between an acid and a base that produces water and a salt.
10. Decomposition Reactions – Reactions where one compound breaks down into two or more simpler substances.
12. – A substance that has a pH below 7 and produces hydrogen ions (H⁺) in water.
15. – A substance used to eliminate or control pests.
16. – A reaction that releases heat energy.
17. – A mixture of two or more metals or a metal and another element.
18. – The starting substances in a chemical reaction.