Across
- 1. how to measure how acidic something is
- 3. makes up 21% of the air we breathe
- 5. saturated hydrocarbon
- 6. what does H20 stand for
- 7. makes up 78% of the air we breathe
Down
- 2. what does H on the periodic table stand for
- 4. what does the C on the periodic table stand for