Chemical Reactions

3. The energy stored in the chemical bonds of a substance
4. When a single compound breaks down into two or more products
9. The substances present after a chemical reaction occurs
10. Reactions that absorb energy from the surroundings
11. The mass of the reactants always equals the mass of the products
13. A reaction involving the exchange of positive ions between two compounds
14. Reactions that release energy to the surroundings
16. Energy is neither created nor destroyed in a chemical reaction
17. When one element replaces another element in a compound
18. This theory states that bonds are broken when molecules collide

1. A chemical; equation that does not indicate
2. These are used to balance the chemical equation
5. A chemical change that happens when an element or compound reacts with oxygen
6. A compound composed of hydrogen and carbon
7. The relative reactivities of elements within groups
8. When tow or more substances react to from a single new substance
12. The speed at which reactants become products
15. Substances present before the chemical reaction occurs