Calculate the number of nitrogen atoms in a 90.0g sample of dinitrogen tetroxide N2O4. Be sure your answer has a unit symbol if necessary, and round it to 3 significant digits.

there are 1.178*10²⁴ atoms of N in the sample

Explanation:

Assuming that the dinitrogen tetroxide is pure (contains no impurities) then

number of atoms of N in the sample = number of moles in the sample * number of molecules per mole * number of N atoms per molecule

- number of atoms per mole = 6.023*10²³ molecules/mole (Avogadro's number)

- number of N atoms per molecule = 2 N atoms/molecule

-number of moles in the sample = mass of N2O4 / molecular weight of N2O4

molecular weight of N2O4 = 2 * (14 gr/mol) + 4 * (16 gr/mole) = 92 gr/mole

thus

number of moles in the sample = 90 gr / 92 gr/mole = 90/92 mole

therefore

number of atoms of N in the sample = 90/92 mole * 6.023*10²³ molecules/mole * 2 N atoms/molecule = 1.178*10²⁴ atoms of N