chapter 2 crossword

5. a number in front of a chemical formula in an equation that indicates how many molecules or atoms of each reactant and product are involved in a reaction
10. a rapid reaction between oxygen and fuel that results in fire
11. a characteristic of a substance that describes its ability to change into different substances
13. a substance that enters into a chemical reaction
15. the minimum amount of energy needed to get a chemical reaction started
19. the process in which substances undergo chemical changes that result in the formation of new substances
21. anything that has mass and occupies space
22. a material that increases the rate of reaction by lowering the activation energy
23. a chemical reaction in which two or more simple substances combine to form a new, more complex substance
24. a biological catalyst that lowers the activation energy of of reactions in cells
25. The principle stating that matter is not created or destroyed during a chemical reaction

1. a chemical reaction that breaks down compounds into simpler products
2. a reaction that releases energy in the form of heat
3. a change to the physical properties of a substance.
4. a material that decreases the rate of a reaction
6. the amount of one material in a certain volume of another material
7. a substance formed as a result of a chemical reaction
8. the study of the properties of matter and how matter changes
9. a characteristic of a substance that can be observed or measured without changing the identity of the substance
12. a material that releases energy energy when it burns
14. chemical reactions in which the reactants absorb heat energy from the surroundings to form products.
16. An easy way to show a chemical reaction using symbols
17. a solid that forms a solution during a chemical reaction
18. a system in which matter can enter from or escape to the surroundings
20. a system in which no matter is allowed to enter or leave