I can’t see the picture where’s it at
Mg gained mass because it went from being a single element (on the reactant side) to being a molecule (on the product side).
The reaction for what was describe in the problem is:
N₂ + 3 O₂ --> 2 NO₃
The reactants involved are nitrogen and oxygen gas. From the word itself, oxygen is an oxidizing agent. <em>Therefore, this reaction is an oxidation reaction due to the presence of the oxidizing agent.</em>
The answer to your question is nitrogen dioxide
There would be 79 electrons present in each atom of gold. I hope this helps :)
