Question

A solution of pentane and ethanol (CH,CH,OH) is boiling at 50.7 °C. A sample of the vapor above the solution is cooled until it condenses. This condensed sample is analyzed, and turns out to be 90.% pentane by mass. Calculate the percent by mass of pentane in the boiling solution. Here's some data you may need: normal boiling point density vapor pressure at 50.7 °C pentane 36. °C 1192. torr ethanol 78. °C 246. torr Be sure your answer has the correct number of significant digits. Note for advanced students: you may assume the solution and vapor above it are ideal. [%

Calculate the percent by mass of pentane in the boiling solution.
pleaseee indicate the answer in bold !! thank you

Answer 1

in vafo-bhase, mass of mass of @ghia x 100 = CHSOH go n, x 72 x 100 x 46 =90 Me= 0.575 ng Yo = t = 0.3650 n, tha ; Y2 = 0.635

Protal x y = x,x Prap Ptotal & Y = H₂+ Puap -(i) - " dividing ris and (iij we get 20 20 in Boiling Soln : .3650 x 946 = 0.1186 635 1192 x2 x,,R in boiling → mole fraction solution nei - 0.1186 - 1 mass of C5 Hię 1 100 mass of Chgok in Boiling Soln 1186*100*72 46 = 18.567.