133.7 g C2H5OH 53.6 g C3H8O3 vapor 40℃ 113 torr

133.7 g C2H5OH 53.6 g C3H8O3 vapor 40℃ 113 torr

 

 

The vapor pressure of a solution containing 53.6 g glycerin (C3H8O3)

in 133.7 g ethanol (C2H5OH) is 113 torr at 40℃.

Calculate the vapor pressure of pure ethanol at 40℃

assuming that glycerin is a nonvolatile, nonelectrolyte solute in ethanol.

 

---------------------------------------------------

 

P_용액 = X_용매 × P°_용매

( 참고 https://ywpop.tistory.com/2646 )

 

 

 

C3H8O3의 몰질량 = 92.09 g/mol 이므로,

53.6 g / (92.09 g/mol) = 0.582 mol

( 참고 https://ywpop.tistory.com/7738 )

 

 

 

C2H5OH의 몰질량 = 46.07 g/mol

133.7 g / (46.07 g/mol) = 2.902 mol

 

 

 

용매의 몰분율(X_용매)을 계산하면,

2.902 / (2.902 + 0.582) = 0.833

( 참고: 몰분율 https://ywpop.tistory.com/2659 )

 

 

 

P°_용매 = P_용액 / X_용매

= 113 torr / 0.833

= 135.7 torr

 

 

 

답: 136 torr

 

 

 

 

[키워드] 순수한 에탄올의 증기압 기준문서, FAQ dic

 

[①22/06/10]