#### Answer

74 g/mol

#### Work Step by Step

We are given that the mass of vapor is0.846g, the volume of the bulb is 354 $cm^3$, the pressure is 752 torr and the temperature is 100C. To find the molar mass, we can use the formula M = dRT/P, but first we need to find the density. Given that 0.846g takes up a volume of 354$cm^3$ we need to convert the 354 $cm^3$ in to Liters. Given that a cubic centimeter, or cc ($cm^3$) is equivalent to a mL, then we have 354mL, which is 0.354L. Then we have 0.846g/0.354L =2.390g/L. We now convert the pressure from torr to atm:
752 torr * (1 atm/ 760torr) = 0.989 atm
and the temperature to Kelvin by adding 273, which is 373K
Last we have M = dRT/P = (2.390 g/L * 0.0821 * 373K) / 0.989 atm = 74 g/mol