science

4. reaction a chemical reaction that releases thermal energy
5. a substance produced by a chemical reaction
6. a type of chemical reaction in which two or more substances combine and form one compound
9. a chemical reaction in which a substance combines with oxygen and releases energy
11. a number placed in front of an element symbol or chemical formula in an equation
12. a substance that increases reaction rate by lowering the activation energy of a reaction
14. a substance that slows, or even stops, a chemical reaction
15. a starting substance in a chemical reaction
16. of mass law that states that the total mass of the reactants before a chemical reaction is the same as the total mass of the
17. a process in which atoms of one or more substances rearrange to form one or more new substances
18. a catalyst that speeds up chemical reactions in living cells

1. a type of chemical reaction in which one element replaces another element in a compound
2. after the chemical reaction
3. a type of chemical reaction in which one compound breaks down and forms two or more substances
7. a type of chemical reaction in which the negative ions in two compounds switch places, forming two new
8. a description of a reaction using element symbols and chemical formulas
10. energy the minimum amount of energy needed to start a chemical reaction
13. reaction a chemical reaction that absorbs thermal energy