Answer : The balanced chemical equation will be:
(i) 
(ii) 
Explanation :
Balanced chemical equation : It is defined as the equation in which total number of individual atoms on the reactant side is equal to the total number of individual atoms on product side.
Part (i):
The balanced chemical equation will be:

This reaction is a single displacement reaction in which most reactive element (potassium) displaces the least reactive element (hydrogen) form their solution.
Part (ii):
The balanced chemical equation will be:

This reaction is a single displacement reaction in which most reactive element (zinc) displaces the least reactive element (magnesium) form their solution.
Answer:
332.918g O2
Explanation:
I'm having some issues with the work however, your final answer should be 332.918g O2
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Answer:
Oceans, Fossil fuels, atmosphere
Answer:
atomic number
Explanation:
atomic number is the number of protons