Apparatus
Bunsen burner
A pair of tongs
A heat proof mat
Three 250 cm
beakers
Chemicals
The quantities given are for one demonstration
75 cm
of ethanol
A few grams of sodium chloride (common salt)
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Before the Demonstration
Prepare some pieces of paper about the size of a £5 note.
Prepare three beakers - one containing about 50 cm
of water; the second containing about 50 cm
of ethanol; and the third containing a mixture of 25 cm
of water mixed with 25 cm
of ethanol with a little sodium chloride dissolved in it.
The Demonstration
Soak a piece of paper in water and try to ignite it by holding it
with tongs in a yellow Bunsen flame. It will not ignite.
Soak a second piece in ethanol. This will ignite easily. The alcohol
will burn and ignite the paper, which will burn away.
Soak a third piece in the alcohol-water mixture and hold it in the
Bunsen flame. This time the alcohol will ignite and burn away, but
the paper will not.
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