key terms

1. chemical substance that is present at the start of a chemical reaction
3. the smallest component of an element having the chemical properties of the element
4. lasting attraction between atoms or ions
6. a change of materials into another, new materials
7. the process of diffusing; the intermingling of molecules in gases and liquids
9. process of going into solution
10. substances that react with acids
13. essential structural component of living cells
14. a chemical substance formed as a result of a chemical reaction
15. a thermodynamic quantity representing the amount of energy in a system
16. the material involved in the change is structurally the same before and after the change
21. the degree of hotness or coldness of a body or environment
23. an essential structural component of living cells and source of energy for animals
24. several complex proteins that are produced by cells and act as catalysts in specific biochemical reactions
26. the simplest structural unit of an element or compound
27. organic compounds that contain both amino and carboxylic acid

2. a substance formed by chemical union of two or more elements
3. fibrous band of scar tissue that binds together
5. a substance that stops an activity
8. the intermolecular force that holds together the molecules in a solid or liquid
11. any of various water-soluble compounds having a sour taste and capable of turning litmus red and reacting with a base to form a salt
12. a substance that initiates or accelerates a chemical reaction without itself being affected
15. a chemical substance that cannot be broken down into other substances.
17. white crystalline carbohydrate used as a sweetener and preservative
18. the capacity of a physical system to do work
19. characterized by opposite extremes
20. any of a large class of chemical compounds in which one or more atoms of carbon are covalently linked to atoms of other elements
22. that which has mass and occupies space
25. the basic structural unit of nucleic acids