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Posted by Lisa (U15482879) on Saturday, 2nd March 2013
Iron reacts with oxygen to form iron oxide.
Iron wool was placed in the bottom of a wet test tube.
The test tube was then put in a beaker of water (upside down)
After some time the water level in the test tube rose and some of the iron wool had formed iron oxide.
Explain why the water level in the test tube rose during the experiment.
PLEASE HELP??!!!! I have looked all over for the answer. My dad has tried explaining it and I just don't understand.
Posted by The Bitesize Science Teacher (U14392404) on Saturday, 2nd March 2013
The oxygen that the iron reacts with comes from the air trapped in the test tube at the start. When the iron reacts with this oxygen over the next few days, it removes the oxygen from the trapped air. This makes the volume of air go down and so the water rises.
As air is about 21% oxygen, the volume will go down by this amount. The experiment is one way to measure the percentage of oxygen in the air. This Bitesize page describes another way to do this: www.bbc.co.uk/school...
I hope this helps.
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