chapter 5

3. the amount of one material in a certain volume of another material
4. 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
5. energy, the minimum amount of energy needed to start a chemical reaction
9. a material that decreases the rate of a reaction
10. change, any change that alters the form or appearance of a substance but does no change it into another’s substance
12. a chemical reaction that breaks down compounds into simpler products
14. of Conservation of mass, the principle that the total amount of matter is neither created nor destroyed during any chemical or physical change
15. change, a change in matter that produces one or more new substances

1. a reaction in which one emmental replaces another in a compound or when two events in different compounds trade places
2. reaction, a reaction that absorbs energy
4. a material that increases the rate of a reaction by lowering the activation energy
6. a chemical reaction in which two or more simple substances combine to form a new (more complex) substance
7. 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
8. substances that undergo the chemical change
11. reaction, a reaction that releases energy (usually in the form of heat)
13. the new substances that form