A compound is 42.9% c , 2.4% h , 16.7% n , and 38.1% o , by mass. addition of 6.00 g of this compound to 50.0 ml benzene, c6h6 (d=0.879g/ml) , lowers the freezing point from 5.53 to 1.37 ∘c .what is the molecular formula of this compound?