In an Ostwald-Walker experiment dry air is passed first through bulbs containing a solution of $5.0\mathrm{g}$ of a non-volatile non-electrolyte in $90\mathrm{g}$ of water, then through bulbs of pure water, and finally through a drying agent. The solution bulbs lose $3.929\mathrm{g}$ and the pure-water bulbs lose $0.071\mathrm{g}$. The relative lowering of vapour pressure equals (loss in pure-water bulbs)/(total loss). Taking $M(\mathrm{H}{}_2\mathrm{O})=18\mathrm{g}\mathrm{mo}{\mathrm{l}}^{-1}$ and Raoult's law exactly, find the molar mass of the solute to the nearest integer.

Numerical answer type, answer in g/mol, tolerance 0.5.