Physics

Physics · thermodynamics

Problem

A. Determine the boiling temperatures of the liquids A and B under the pressure

p_{0}

. Given constants: Consider two liquids A and B insoluble in each other. The pressures

p_{i}(i=\mathrm{A}

\mathrm{B})

of their saturated vapors obey, to a good approximation, the formula:

\ln \left(p_{i} / p_{o}\right)=\frac{\alpha_{i}}{T}+\beta_{i} ; \quad i=\mathrm{A} \text { or } \mathrm{B}

where

p_{o}

denotes the normal atmospheric pressure,

T

- the absolute temperature of the vapor, and

\alpha_{i}

and

\beta_{i}

(

i=\mathrm{A}

\left.\mathrm{B}\right)

- certain constants depending on the liquid. (The symbol

\ln

denotes the natural logarithm, i.e. logarithm with base

e=2.7182818 \ldots)

The values of the ratio

p_{i} / p_{0}

for the liquids

\mathrm{A}

and

\mathrm{B}

at the temperature

40^{\circ} \mathrm{C}

and

90^{\circ} \mathrm{C}

are given in Tab. 1.1. Table 1.1

The errors of these values are negligible.