Investigating the causes of Corrosion to Iron
Hypothesis
I believe that iron needs both oxygen and water in order to form iron oxide (rust). I also believe that iron oxide formation will not occur when neither oxygen nor water is present (test tube numbers 2, 3, 5, and 8).
Certain factors can affect the reaction rate: limiting reactants i.e. the amount of water, oxygen and iron present and higher temperatures cause a faster reaction rate.
Other reactants may change the reaction completely or alter the reaction rate. In order to test this I added magnesium and salt. Different concentrations of these reactants (diluted and saturated) should also change the reaction rate.
Iron can be coated by a more reactive metal i.e. zinc. This is called galvanization. The zinc is higher up in the reactivity series which causes the oxygen and water to react with the zinc. This is called sacrificial protection because the zinc sacrifices itself to protect the iron. Zinc is often used to protect iron.
The formula for this reaction is:
Oxygen + Iron + Water → Iron Oxide
O2 + 2Fe + H2O → Fe2O3 + H2
Health and Safety
The chemicals that are being used are not dangerous provided they are handled as directed by the tutor. Take care when pouring the boiled water into the test tube as it is still hot.
