In my garden I have a metal statue made of an alloy. Which consists of mainly magnesium. I have noticed that during the year it corrodes at different rates. I will now devise an experiment to investigate the causes of this problem.
The reactions of magnesium with certain elements are detailed below
(A) Magnesium with Water
Magnesium does not react readily with cold water but in steam the magnesium lights and leaves behind magnesium oxide and releases hydrogen gas.
(B) Magnesium with Air
Magnesium reacts slowly with air forming an oxide layer on the surface.
(C) Magnesium with Acid
Magnesium reacts vigorously with acid leaving a solution of magnesium sulphate and hydrogen below is the word equation.
Mg + H2So4 MgSo4 + H2
How is acid rain formed?
Some air pollutants are acidic gases particularly sulphur dioxide and nitrogen dioxide. These gases are formed when fuels are burned especially in car engines and in power stations.
After they have been released they react with the gases in the air and with the rain-water. Reactions like this make rain water acidic. Acid rain has a ph of between 5 and 2 the equation for acid rain is
H2O + SO2 H2SO3
Some factors affecting the reaction rate are as follows,
At higher temperatures particles are moving faster so there are more collisions. Also the collisions are more energetic. More collisions have an energy greater than the activation energy so the reaction is faster. The diagram below helps show this.
Low Temperature High Temperature
The catalyst seems to lower the activation energy for the reaction. Many more reactions are "successful" and the reaction is faster. The diagram below helps show this.
No Catalyst With Catalyst
In solutions of higher concentration and in gases at higher pressure, particles are closer...