Using the combined gas law, where PV/T = constant, we first solve for PV/T for the initial conditions: (4.50 atm)(36.0 mL)/(10.0 + 273.15 K) = 0.57213.
Remember to use absolute temperature.
For the final conditions: (3.50 atm)(85.0 mL)/T = 297.5/T
Since these must equal, 0.57213 = 297.5/T
T = 519.98 K
Subtracting 273.15 gives 246.83 degC.
Molar/molecular mass? methanol's chemical formula is: CH3OH . Mass of C = 12, Mass of O = 16, Mass of H = 1
So, molar mass of methanol is just a sum of masses of elements I listed above.
Mass of methanol = 12+3x1+16+1=32 (grams/mole or units)