key terms

2. in chemistry when two or more elements or compounds combine to make more complex susbstance the process is called
6. a material used to decrease the rate of a reaction is an
8. when one element replaces another in compound or when two elements in different compounds trade places the process is called
10. is material that releaes energy when it burns
12. is a number place in foront of a chemcial formula in an eqaution
13. is the amount of a substance in a given volume
16. property is a characteristic of a substance taht describes its abitly to change into other substance
17. reaction is a reaction in which energy is absorbed
21. system matter is not allowed to eneter or leave
22. system matter can enter from or escape to the surroundings
23. in contrast to a synthesis reaction a process called breaks down compounds into simpler products
24. change is any change that alter the form or apperance of a substance but that does not make the substance change into another substance.

1. is a material that increases the rate of a reaction be lowering the activation energy.
3. the cells in your body comtains biological catalysts called
4. property a characteristic of a substance that can be observed without changing the substance into another substance
5. equation is a short easy way to show chemical reaction unsing symbols instead of words
7. the substance you have at the beginning are called the
9. a solid that forms from solution during a chemical reaction is called a
11. of mass this principle is call and it states that during q chemical reaction matter created or destroyed
14. energy is the minimum amount of energy needed to start a chemical reaction
15. the branch of science that deals with the identification of the substances of which matter is composed; the investigation of their properties and the ways in which they interact, combine, and change; and the use of these processes to form new substances.
16. fire is the result of a rapid reaction between oxygen and a substance called a fuel
18. anything that has mass and takes up space
19. reaction A change in matter that produces one or more new substances is a chemical change or
20. when the reaction is complete you have new substances called