.07! you divide 7 by 100%
Answer:

Explanation:
From the given information, since the molecular mass of the ion M+ is not given;
Let's assume M+ = 58.0423
So, by applying the 13th rule;
we will need to divide the mass by 13, after dividing it;
The quotient n = no. of carbon; &
The addition of the quotient (n) with the remainder r = no. of hydrogen.
So;

So;


From the given information; we have oxygen present, so since the mass of oxygen = 16, we put oxygen in the molecular formula by removing
. Also, since the mass is an even number then Nitrogen is 0.
So, we have:

So multiply number of moles x number of atoms/mole = 1.8066 x 10^24 atoms of H2. One mole of any gas at STP has a volume of 22.4 L. So first determine the number of moles of gas you have.
for example do 7

that 's what I think