In: Chemistry
Ethanol has a heat of vaporization of 38.56kJ/mol and a normal boiling point of 78.4 ℃ .
What is the vapor pressure of ethanol at 17 ℃?
Express your answer using two significant figures. Units in torr
logP2/P1 = Hv/2.303R [1/T1 -1/T2]
T1 = 170C = 17 + 273 = 290K
T2 = 78.40C = 78.4 + 273 = 351.4K
P1 =
P2 = 760torr
Hv = 38.56Kj/mole = 38560J/mole
logP2/P1 = Hv/2.303R [1/T1 -1/T2]
log760/P1 = 38560/2.303*8.314 [1/290 -1/351.4]
= 2013.87(0.003448-0.00284)
= 1.2244
log760/P1 = 1.2244
760/P1 = 10^1.2244
760/p1 = 16.7648
P1 = 760/16.7648 = 45.33 torr >>>>answer or 43 torr