Combustion and Flame

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