Unit 2

3. substance that speeds up the rate of a chemical reaction
4. bond- type of bond between atoms in which the electrons are shared
5. capacity (specific heat)-- the amount of heat needed to raise the temperature of 1 gram of a substance 1 degree Celsius (°C)
6. pure substance that consists entirely of one type of atom
9. found in the nucleus that has no charge
11. number-the number of protons in the nucleus of an atom, which determines the chemical properties of an element and its place in the periodic table (also equals the number of electrons in an element)
13. energy- energy that is needed to get a reaction started
14. a combination of 2 or more elements connected by bonds
15. action-- tendency of water to rise in a thin tube
16. reaction- a reaction that absorbs energy (absorbs heat)
18. force of attraction between different kinds of molecules
20. reaction- a reaction that releases energy (gives off heat)
22. reactant of an enzyme-catalyzed reaction
25. symbol- one- or two-letter abbreviation for a chemical element name
26. (chemistry definition) the center of an atom, which contains the protons and neutrons

1. formed as a result of a chemical reaction
2. electron- electron found in the outermost shell of an atom; helps to determine bonding
7. reaction- process that changes, or transforms, one set of chemicals into another set of chemicals
8. positively charged particle found in the nucleus of an atom
10. charged particle that orbits the nucleus in the electron cloud
12. basic unit of matter
17. attraction between molecules of the same substance
18. mass-equal to the total number of protons and neutrons in the nucleus of an atom (based on isotopes)
19. in a molecule, uneven distribution of electrons (results in (+) and (-) poles) ex. water
21. bonding-- weak attraction between a hydrogen atom and another atom
23. elements or compounds that enter into a chemical reaction
24. biological catalysts