posted by regina on .
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?
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
molar mass of which is 60 g mole^-1
so molecular formula is