Vocab

6. of mass
8. equation a description of a reaction using element symbols and chemical formulas
12. a catalyst that speeds up chemical reactions in living cells
13. reaction a chemical reaction that absorbs thermal energy
15. a chemical reaction in which a substance combines with oxygen and releases energy
17. after the chemical reaction
18. a substance that slows, or even stops, a chemical reaction
19. that states that the total mass of the reactants before a chemical reaction is the same as the total mass of the

1. energy the minimum amount of energy needed to start a chemical reaction
2. reaction a process in which atoms of one or more substances rearrange to form one or more new substances
3. a substance that increases reaction rate by lowering the activation energy of a reaction
4. a type of chemical reaction in which one element replaces another element in a compound
5. a number placed in front of an element symbol or chemical formula in an equation
7. a starting substance in a chemical reaction
9. a type of chemical reaction in which two or more substances combine and form one compound
10. a type of chemical reaction in which one compound breaks down and forms two or more substances
11. a substance produced by a chemical reaction
14. a type of chemical reaction in which the negative ions in two compounds switch places, forming two new
16. reaction a chemical reaction that releases thermal energy