chemical interactions

2. during a chemical reaction, matter is not created or destroyed.
5. a characteristic of a substance that can be observed without changing the substance into another substance.
7. use chemical formulas and other symbols instead of words to summarize reaction.
9. a material that increases the rate of a reaction by lowering the activation energy.
11. a reaction that releases energy in the form of heat.
13. the result of fire
14. a characteristic of a substance that describes its ability to change into other substances.
19. the cells in your body contain biological catalysts.
20. a material that releases energy when it burns
23. matter is not allowed to enter or leave.
24. can be described in the terms of two kinds of properties, physical and chemical.
25. a material that used to work by preventing reactants from coming together.
26. the minimum amount of energy needed to start a chemical reaction.

1. a number placed in front of a chemical formula in am equation
3. the study of matter and how matter changes
4. a solid that forms from solution during a chemical reaction
6. when the reaction is complete, you have new substances.
8. A change in matter that produces one or more new substances
10. the amount of a substance in a given volume
12. a reaction in which energy is absorbed
15. any change that alters the form or appearance of a substance but that does not make the substance into another substance.
16. breaks down compounds into simpler products.
17. matter can enter from or escape to surroundings.
18. when two elements in different compounds trade places.
21. the substances you have at the beginning.
22. when two or more elements or compounds combine to make more complex substances.