Question

mass= 3.8721g
temperature= 102 degrees Celsius
volume= 156ml
atmospheric pressure= 755.0 mm Hg

calculate the molar mass using the ideal gas law

Answer 1

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.

Answer 2

so all the units i have to change is just for temperature and then leave the rest as they are

Answer 3

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