Answer : There are 7.0 moles of oxygen in the formula.
Explanation :
The chemical formula of nickel tetracarbonyl is Ni(CO)₄.
We can see that there are 4 carbon atoms and 4 oxygen atoms which together form 4 carbonyl (CO) groups.
Therefore the mole ratio of C to O is 1 : 1.
Let us use this as a conversion factor to find moles of oxygen.
We have 7.0 moles of carbon in the formula.
The moles of O can be calculated as,

There are 7.0 moles of oxygen in the formula.
Answer:
C
Explanation:
It is formed as a result of a reaction between two non-metals
I'm assuming that by "miles" you mean moles.
If O2 is the excess reactant, that means Fe is the limiting reactant. That means that the amount of product being formed depends on the amount of Fe reactant present. To calculate the moles of Fe2O3 formed, start with the given 6.4 moles of Fe and use the mole to mole ratio given by the reaction as shown below:
6.4 mol Fe x

=
3.2 mol Fe2O3
Just add more detail in the second experiment explain every little thing.
I’d say A. They are theoretical in the fact that they have not been observed directly, but have been confirmed to exist through experimentation.