Answer:
a)
b)
Explanation:
a) The reaction:

The free-energy expression:

![E=E_{red}-E_{ox]](https://tex.z-dn.net/?f=E%3DE_%7Bred%7D-E_%7Box%5D)
The element wich is reduced is the Fe and the one that oxidates is the Mg:

The electrons transfered (n) in this reaction are 2, so:


b) If you have values of enthalpy and enthropy you can calculate the free-energy by:

with T in Kelvin


I know what you're asking but I don't think the question is stated properly. Technically, an atom will not join with an "oxide" ion; i.e., the oxide ion is an atom of oxygen to which two electrons have been added. An oxide ion will add to 2 K ions or 1 Ca ion. The K ion has lost just one electron so it takes two of them to equal the 2- charge on the oxide ion whereas the Ca ion has lost two electrons and it takes only one of them to equal the charge on the oxide ion.
Answer:
The yearly release of
into the atmosphere is
.
Explanation:

Annual production of CaO = 
Moles of CaO :

According to reaction, 1 mole of CaO is produced along with 1 mole of carbon-dioxide.
Then along with
of CaO moles of carbon-dioxide moles produced will be:
of carbon-dioxide
Mass of
moles of carbon-dioxide:

The yearly release of
into the atmosphere is
.
Because it is a covalent bond meaning that they share the electrons to achieve full valence.
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