Question

A compound is composed of 19.998% carbon, 3.331% hydrogen, 23.320% nitrogen, and 53.302% Oxygen. Its molar ass is 120.07 gram/mole. What are the empirical and molecular formulas?

Answer 1

There is a good rote way to do these:

19.998% carbon, 3.331% hydrogen, 23.320% nitrogen, and 53.302% oxygen

Assume 100 g

19.998g carbon, 3.331g hydrogen, 23.320g nitrogen, and 53.302g oxygen

divide by molar mass of each

19.998/12 carbon, 3.331/1 hydrogen, 23.320/14 nitrogen, and 53.302/16 oxygen

1.667 mole carbon, 3.331 mole hydrogen, 1.667 mole nitrogen, and 3.331 mole oxygen

divide by smallest to get ratio

1 mole carbon, 2 mole hydrogen, 1 mole nitrogen, and 2 mole oxygen

so empirical is

CH2NO2

molar mass of which is 60 g mole^-1

so molecular formula is

C2H4N2O4

1,1-dinitroethane ???