Across
- 4. The chemical process of burning
- 5. The hot, glowing part of a fire
- 9. A substance that is used up during a chemical reaction
- 10. A gas that supports combustion and is needed for respiration
- 11. The amount of a substance present in a mixture
- 12. The mixture of gases that surrounds us
- 14. Substances that can be burned to release energy
- 16. A device used to put out a fire
- 18. The process of breathing air into the lungs
- 20. The process cells use to release energy from food
- 21. To cause a fire to stop burning
Down
- 1. A substance formed during a chemical reaction
- 2. The ability of a substance to burn
- 3. A state of matter that spreads out to fill its container
- 5. A substance that can be burned to release energy
- 6. Relating to electricity or electric current
- 7. dioxide A gas produced during respiration and breathed out by animals
- 8. A process in which substances are changed into new substances
- 13. The layer of gases surrounding Earth
- 14. Able to catch fire and burn easily
- 15. To breathe air out of the lungs
- 17. A chemical reaction involving oxygen
- 19. The process of starting combustion