rusting of steel can be prevented by coating the steel with a layer of zinc. Explain, in terms of electron transfer, why steal does not rust even if the layer of zinc is scratched so that the steal is exposed to air and water.

Wouldn't rust because zinc will lose electrons more readily than iron and will therefore oxidize first.

Explanation:

This process whereby rusting of steel is prevented by coating the steel with a layer of zinc is known as galvanization.

Now, in this process, the steel object will be coated in a thin layer of zinc. This coating will prevent oxygen and water from reaching the underneath metal since the zinc will also act as a sacrificial metal.

Now, Zinc is used because it has a lower reduction potential than iron and thus it will get easily more oxidized than iron. Which means the zinc will lose electrons more readily than iron.

Also, since zinc has a lower reduction potential, it is therefore the more active metal. Thus, even if the zinc coating is scratched and the steel is exposed to moist air, the zinc will still get to oxidize before the iron.

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"