Across
- 1. Oxides of sulphur and nitrogen dissolve in rain
- 3. Unburnt carbon is present in the ______ zone of flame
- 9. Substances that vaporize form ______
- 12. Increase in the concentration of carbondioxide increases the temperature
- 13. Substances that catch fire at room temperature
- 14. Substances that are combustible and used as a source of energy
- 16. The lowest temperature at which a substance catches fire
- 18. Gas that is needed for burning
- 19. Amount of heat produced per kg of fuel
Down
- 2. Substances that can burn
- 4. This is a cleaner fuel as compared to petrol and diesel
- 5. Burning firecrackers
- 6. Unit of energy
- 7. Heat and light produced in sun by ______ reaction
- 8. Reaction with oxygen to produce heat, gases and other substances
- 10. Substances that catch fire easily
- 11. Incomplete combustion of fuel produces this gas
- 15. Hottest part of the flame
- 17. Gas burns and produces heat and light quickly. This is ______ combustion