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Bunsen burner. External View. Bunsen burner. Barrel : to raise the flame to a suitable height for burning or heating. Air-hole: to allow air to enter the burner. Jet : to enable the gas to rush out of the gas supply and to draw in air.
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Bunsen burner External View
Bunsen burner Barrel: to raise the flame to a suitable height for burning or heating Air-hole:to allow air to enter the burner Jet:to enable the gas to rush out of the gas supply and to draw in air Collar:to regulate the amount of air entering the burner through the air-hole Base:to support the burner so that it will not topple Gas tap:to control the flow of gas to the Bunsen burner
Bunsen burner Internal View
Lighting the Bunsen burner 1. Close the air-hole. 2. Put the gas lighter at the top of the barrel. 3. Turn on the gas tap.4. Strike the lighter to get a luminous flame.
almost colourless zone of complete combustion blue zone of partial combustion hottest part dark zone of unburnt gas A Non-luminous Flame Bunsen burner
Non-Luminous Flame • occurs when the air-hole is open, allowing sufficient air into theburner • Blue • steady • very hot • hottest part of the flame is just above the tip of the blue zone
orange zone of incomplete combustion blue zone of partial combustion almost colourless zone of complete combustion dark zone of unburnt gas A Luminous Flame Bunsen burner
Luminous Flame • occurs when the air-hole is closed and very little air is allowed to mix with the gas • Soot is deposited on apparatus • orange • appears flickering and unsteady • not very hot
flame at jet Strike Back
Strike Back • occurs when there is too much air entering air-hole • instead of burning at the top of the barrel, the gas burns at the jet • when a strike back • occurs, turn off burner immediately
put wire gauze (gauze mat) on tripod stand • put beaker of liquid on it • light Bunsen burner and then push it under the tripod stand • turn off burner when the liquid reaches required temperature Heating a Liquid in a Beaker
hold test tube with test tube holder • ensure that the mouth of the test-tube is pointing away from myself and others • slant test-tube at an angle of about 45O and heat it in the hottest part of a Bunsen flame • move the test-tube through flame • liquid to be heated should occupy no more than one-third test-tube Heating a Liquid in a Test tube