Chapter 2

4. a characteristic that has the ability to change into another substance
5. matter in not created nor destroyed
7. the minimum amount of energy needed to start a chemical reaction
10. The amount of one material in a certain volume of another material.
11. a solid that form from solution during a chemical reaction
14. the substances you have at the beginning
16. matter that can enter or leave their environment
18. the substances when you complete the reaction
19. two or more elements or compounds combine to make more complex substances
20. A material that increases the rate of a reaction by lowering the activation energy.
21. a easy way to show a chemical reaction using symbols instead of roles
23. Any change that changes or alters the appearance of a substance
24. a reaction that releases energy in the form of heat

1. a material used to decrease the reaction rate.
2. breaks down compounds into simpler forms
3. a change in matter that one or more new substances
6. a characteristic of a substance that can be observed without changing into another substance
8. a reaction in which energy is absorbed and does not always result in a decrease in temperature.
9. anything that has mass and takes up space
12. matter is not allowed to leave or enter
13. a rapid reaction between oxygen and a substance called fuel
15. When one element replaces another in a compound
17. a material that releases energy when it burns
21. a number placed in front of a chemical formula in an equation
22. A biological catalyst that lowers the activation energy of reactions in cells.