Chapter 5

3. change, a change in matter that produces one or more new substances
5. the amount of one material in a certain volume of another material
7. of Conservation of mass, the principle that the total amount of matter is neither created not destroyed during any chemical or physical change
10. reaction, a reaction that releases energy (usually in the form of heat)
11. reaction, a reaction that absorbs energy
13. a reaction in which one emmental replaces another in a compound or when two events in different compounds trade places
14. 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
15. a chemical reaction in which two or more simple substances combine to form a new (more complex) substance

1. the new substances that form
2. energy, the minimum amount of energy needed to start a chemical reaction
4. a material that decreases the rate of a reaction
6. a material that increases the rate of a reaction by lowering the activation energy
8. a chemical reaction that breaks down compounds into simpler products
9. change, any change that alters the form or appearance of a substance but does no change it into another’s substance
11. a type of protein that speeds up a chemical reaction in a living thing (a biological catalyst that lowers the activation energy of reactions in cells
12. substances that undergo the chemical change