Unit 1

2. A scale from 0 to 14 used to measure how acidic or basic a substance is (0-6 is acidic, 7 is neutral, 8-14 is basic).
4. A material made of only one kind of particle; it can be an element or a compound.
7. A pure substance made of only one kind of atom.
10. Anything that has mass and takes up space.
11. A type of mixture where one substance is completely dissolved in another.
12. Substances that release hydroxide ions (OH⁻) in water; they are basic.
14. Substances that release hydrogen ions (H⁺) in water; they are acidic.
15. Tiny pieces that make up matter, like atoms and molecules.
16. A number that shows how acidic or basic a substance is.
17. When water molecules stick to each other.
18. The smallest unit of an element; makes up all matter.
20. A property of liquids where the surface acts like a stretched skin due to water molecules sticking together.
21. A one- or two-letter abbreviation that represents an element (like H for hydrogen).

1. A set of symbols and numbers that show the elements and number of atoms in a compound.
3. The movement of water through small spaces due to adhesion and cohesion.
5. The movement of substances from one place to another.
6. A combination of two or more substances that are not chemically joined.
8. Two or more atoms bonded together.
9. A chemical that changes color to show if something is an acid or a base.
12. A substance with a pH above 7; feels slippery and tastes bitter.
13. A mixture that looks the same throughout; the parts are evenly mixed.
14. When water molecules stick to other surfaces.
17. A substance made of two or more different elements chemically bonded together.
18. A substance with a pH below 7; tastes sour and can react with metals.
19. A mixture where you can see the different parts.