chemical reactions

2. more energy required to break bonds than is released when new ones are formed
7. states atoms, ions, and molecules must collide in order to react
9. a change in which one or more substances are converted into new substances
11. starting substances in a chemical reaction
12. activation energy required is less than that released when new bonds form
15. substance that speeds up a chemical reaction without permanently changing itself
16. reaction where energy is given off
18. mass in grams of one mole of a substance
19. an insoluble compound that comes out of solution during this type of reaction

1. when the energy needed to keep a reaction going is thermal
3. when a substance reacts with oxygen to produce energy as heat and light
4. is a state in which forward and reverse reactions or processes proceed at equal rates
5. end substances in a chemical reaction
6. the rate at which reactants change into products
8. two or more substances combine to form another substance
10. one or more substance breaks down into two or more substances
13. represent the number of units of each substance taking part in a reaction
14. way to describe a chemical reaction using chemical formulas and other symbols
17. the amount of a substance that contains 6.02 x 10^23