chemisty

1. reaction: a reaction that takes place when two or more substance react to form new substances
4. system: an experiment in which all reactants and all products of a chemical reaction are accounted for
6. reaction: chemical reaction that absorbs energy
7. amount of mass in a given volume of a substance
8. slow chemical change that occurs when oxygen in the air reacts with a metal
10. chemical reaction that occurs when oxygen reacts with a substance to form a new substance and give off energy
13. 17 elements in the periodic table; the most reactive non-metals
14. respiration: chemical reaction that takes place in cells; food (sugar) reacts with oxygen to produce energy, water, and carbon dioxide p
18. change of state from a liquid to a gas
19. catalyst involved in chemical reactions in living things

1. chemical combination of two or more elements in a specific ratio
2. shell: orbit of electrons around the nucleus of an atom
3. description of a solid that can be stretched into a long wire
5. change of state from a gas to a solid
9. of mass: principle that matter is not created or destroyed in a chemical reaction; the mass of the products always equals the mass of the reactants
11. substance that helps a chemical reaction to proceed more quickly
12. ability of a substance to conduct electricity or heat
15. change of state from a liquid to a solid
16. substance: that helps a chemical reaction to proceed more quickly
17. cloudy mixture in which tiny particles of one substance are held within another and particles cannot be separated out from the other substance