[Google]

The reaction is a Chemical Reaction, due to displacement. The reason for this is because Magnesium is more reactive than zinc so it takes the place of the zinc.

You can have a look at the reactivity series here: http://www.frankswebspace.org.uk/Science...Series.gif

I believe everything below hydrogen is found in the ground, everything above can be broken down with the use of carbon, and everything above carbon, would require electrolysis to break down. This explains why magnesium is more reactive than zinc.

Sorry about before, bring on the next question :15-Cool-20px:

already posted, this time follow the rules.:11-Mad-20px: