chemistry
posted by VICKY .
mass= 3.8721g
temperature= 102 degrees Celsius
volume= 156ml
atmospheric pressure= 755.0 mm Hg
calculate the molar mass using the ideal gas law

Use PV = nRT to solve for n = number of moles. Don't forget that T is in Kelvin.
Then n = grams/molar mass
You know n and grams, solve for molar mass. 
so all the units i have to change is just for temperature and then leave the rest as they are

No. T is in Kelvin.
P is in atmospheres.
V is in L.
Use 0.08206 L*atm/mol*K for R.