The mass of atoms of carbon and 3 molecules of hydrogen : 18 g/mol
<h3>Further explanation
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An atomic mass unit ( amu or "u") is a relative atomic mass of 1/12 the mass of an atom of carbon-12.
The molar mass(molecular mass-formula mass-molecular weight(MW)) of a compound is the sum of the relative atomic mass (Ar) of the constituent elements of the compound
Can be formulated :
M AxBy = (x.Ar A + y. Ar B)
The mass of atom of Carbon(C)⇒Ar = 12 g/mol
The mass of 1 molecule of Hydrogen - H₂(MW) : 2 g/mol
The mass of 3 molecules of Hydrogen : 3 x 2 = 6 g/mol
So the mass of atoms of carbon and 3 molecules of hydrogen :

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When you are asked a question like this, you can always ask yourself this question. Can I change it back after this change? For example, if you are burning wood, you cannot bring it back to wood after you burn it, therefore, it is a chemical change. However, if you boil and evaporate water, you can make the water condense again back into its liquid form. In this case, you cannot bring the tomato back to its raw state. Therefore, cooking raw tomatoes is a chemical change.
The equation of 5m+4=7m+6 is equal to m=-1
The given equation from the problem above is already balance,
N2O5 ---> 2NO2 + 0.5O2
Since, in every mole of N2O5 consumed, 2 moles of NO2 are formed, we can answer the problem by multiplying the given rate, 7.81 mol/L.s with the ratio.
(7.81 mol/L.s) x (2 moles NO2 formed/ 1 mole of N2O5 consumed)
= 15.62 mol/L.s
The answer is the rate of formation of NO2 is approximately 15.62 mol/L.s.