| A | B |
|---|
| acid | a substance that has a pH less than 7 |
| alkali | a soluble substance that has a pH greater than 7 (noun) |
| alkaline | having a pH greater than 7 (adjective) |
| base | a substance that has a pH greater than 7 (noun) |
| *chemical | a substance used in a reaction involving changes to atoms or molecules |
| *hydrogen | a colorless gas that burns easily and is the lightest element in the universe |
| acidic | having a pH less than 7 (adj) |
