copper(II)
oxide.2Cu(s) + O2(g)
2CuO(s)Proportion of Oxygen in the Air.
Oxygen makes up 21%
of the air.
This can be demonstrated by the
reaction
of a fixed amount of air with heated
copper.
Copper will react with oxygen in
the air to form copper(II)
oxide.
copper + oxygen copper(II)
oxide.
2Cu(s)
+ O2(g)
2CuO(s)
A known
amount of air is passed backward and forward
over the heated
copper.
As copper(II) oxide is
formed, oxygen is removed
from the air
and the volume of air in the syringes
is seen to decrease.
When the reaction is complete,
only 80% of the original volume of air remains.
This shows that the proportion of
oxygen in the air is about
20%.
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