Pheromones are compounds secreted by the females of many

Pheromones are compounds secreted by the females of many insect species to attract males. One of these compounds contains 80.78 percent carbon 13.56 percent hydrogen and 5.66 percent oxygen. A solution of 1.00 g of this pheromone in 8.50 g of benzene freezes at 3.37ºC. What are the molecular formula and molar mass of the compound? (The normal freezing point of pure benzene is 5.50ºC.) Kf = 5.12 ºC /m – Can you explain how to get this answer?