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Experiment:To investigate the heating effects of the luminous and non-luminous flames.

Answer Text:
Experiments on Bunsen burner flames.
1. To investigate the heating effects of the luminous and nonluminous flames.
Apparatus:
- Bunsen burners, 250 ml beakers, lighter, stopwatch, tripod stand, wire gauze.
Procedure
- 100#cm^3# of water is put into each of the two 250 ml beakers.
- One beaker is put over a luminous flame while the other is simultaneously put over a non-luminous flame
- Time taken for water to boil is noted for each set up.
- The bottom of each beaker is observed for any changes.
Apparatus

Observations.
- Water heated over the nonluminous flame boiled in a shorter time than the same amount of water heated over a non-luminous flame.
- The bottom of the beaker heated over the nonluminous flame remained clear but the one heated over the luminous flame was covered with black deposits of soot.
Explanations.
- The non-luminous flame is hotter than the luminous flame; hence boils the water faster
- The hottest part of the luminous flame is the outer blue zone.
- Incomplete combustion in the luminous flame leads to production of carbon particles, which when hot glow yellow and on cooling forms black soot on the beaker;
- Incomplete combustion in a non-luminous flame leads to production of carbon (IV) oxide and steam only, hence no soot formation.
Conclusions.
- The non-luminous flame is hotter than the luminous flame.
- The non-luminous flame is cleaner than the luminous flame.