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A10 Steel
wool (iron) changes its mass during combustion
Do
not forget to wear you goggles!
In the previous experiment
you observed that glowing stee wool burns while you blow on it (apparently
exhaled air still contains enough oxygen). In the following experiment
you will test what happens with the mass during combustion.
1.
Left: Transfer as much steel wool on the left pan of your scale
that two metal Liquemin closures are balanced.
2.
Make a small ball from the wool, 3.
use tweezers to hold it above the flame of you burner. 4.
Let it glow, 5. burn it
by blowing into it as long as it is glowing.
Observations:
* Middle: The colour
of the steel wool is darker, some small fibre are molten leaving tiny balls.
* Right: The mass
of the steel wool has increased during combustion. It has become brittle:
You can powder it between your fingers.
Explanation:
There was a chemical
reaction between iron and oxygen of the air. The new substance is made
from iron and oxygen, so its is more heavy than iron.
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modification: 25.10.2001