M Prep | MCAT 2015 Question of the Day - Prep, Practice Questions, and More!

Q:	16g of an unknown, nondissociating substance is dissolved in 1kg of benzene. This solution is noted to boil at 75 degrees celsius, whereas pure benzene boils at 73 degrees Celsius. The ebullioscopic constant, K_b, is 2.5 degreesC*kg/mol. What is the molecular weight of the unknown substance?

15 g/mol

20 g/mol

25 g/mol

30 g/mol