What is the molecular formula of a compound if its empirical formula is #NO_2# and its molar mass is 138.02 g/mole?

1 Answer
Apr 25, 2016

Answer:

138.02 g/mol #-:# molar mass of empirical formulae = whole number,
then
Molecular Formulae = Empirical Formulae #xx# whole number

Explanation:

If the molar mass of 138.02 g/mol has been provided for you,
divide it by the molar mass of #NO_2#.

Nitrogen has a molar mass of 14.0 g/mol, whereas oxygen is 16.0 g/mol
138.02 g/mol #-:# #(1 xx 14.0 +2 xx16.0)#
138.02 g/mol #-:# 46.0 g/mol = 3.00 (rounded to nearest whole number)

Since 3.00 is the whole number, multiply it by the empirical formula.

(#NO_2#)#xx#3.00 = #N_3O_6# is the molecular formula.