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Experiment 7.2A:
What
is given out when a wooden splint burns? (P.16 - 17)
3. Touch接觸 the
outside of the gas jar with your hand.
(a) What do you feel? My hand feels warm / hot
4. (a) Observe the inner wall of
the gas jar.
What do you see on
the inner wall of the gas jar? A layer of mist
(i) What happens to the cobalt chloride
paper? It turns pink.
5. Add 5 cm3 of hydrogencarbonate indicator into the gas jar. Cover the gas jar
with the glass plate immediately. Shake the gas jar gently. Observe the colour
of the indicator.
(a) What happens to the indicator?
It changes from red to yellow.
Discussion:
During the process of burning, the temperature increases
(increases / decreases). This shows
that the burning process gives out heat
energy. After burning, a layer of mist
is found on the inner wall of the gas jar, and it
can turn cobalt chloride paper from blue
to pink. This shows that water vapour is given out
during burning.
The colour of hydrogencarbonate indicator changes
from red
to yellow.
This shows that carbon dioxide is given out
during process.
Conclusion結論:
Ø
The above results show that burning gives out carbon dioxide,
water and heat energy.
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