InterviewSolution
Saved Bookmarks
| 1. |
Heptane and octone form ideal solution. At 373 K, the vapour pressure of the two liquid components are 105.2 K Pa and 46.8 K Pa respectively. If the solution contains 25 g of heptane and 25 g of octane, calculate : Vapour pressure exerted by hepthne Vapour pressure exerted by octane Vapour pressure exerted bythe solution Mole fraction octane in the vapour phase. |
|
Answer» `"No. of moles of heptane" (n_(B))=("Mass of heptane"(C_(7)H_(16)))/("Gram molar mass")=((25g))/((100 g mol^(-1)))=0.25 mol` `"No. of moles of cotanae" (n_(A))=("Mass of heptane"(C_(8)H_(18)))/("Gram molar mass")=((35g))/((114 g mol^(-1)))=0.307 mol` `"Molar fraction of hepthane" (x_(B))=n_(B)/(n_(B)+n_(A))=((0.25 mol))/((0.25 mol+0.307 mol))=0.449` `"Molar fraction of octane" (x_(A))=n_(A)/(n_(B)+n_(A))=((0.307 mol))/((0.25 mol+0.307 mol))=0.551` `"Vapour pressure of pure heptane" (P_(B)^(@))=105.2 kPa` `"Vapour pressure of pure octane" (P_(A)^(@)) = 46.8 kPa` ` (i) "Vapour pressure of heptane" (P_(B)^(@))=P_(B)^(@)x_(B)=(105.2 kPaxx0.449)47.23 kPa` ` (ii) "Vapour pressure of octane" (P_(A))=P_(A)^(@)x_(A)= (47.23+25.79=73.02 kPa)` `(iii) "Total vapour pressure of solution "(P)=P_(A)+P_(B)=(47.23+25.79)=73.02 kPa` (iv)"mole fraction of octane in the vapour phse"= `P_(A)/(P_(A)+P_(B))=((25.79K Pa))/((73.02 K Pa))= 0.353` |
|