Across
- 2. take in
- 3. a result of a chemical reaction
- 4. let go
- 6. the amount of matter in an object
- 9. any substance that has a defined composition
- 11. exit
- 13. light
Down
- 1. absorption
- 2. molecule
- 5. enter
- 7. A system of knowledge about the physical, chemical, and biological universe
- 8. energy that comes from light
- 10. an attraction between atoms
- 12. the starting substances in a chemical reaction