Use the following information to answer questions 2 through 8: Diethyl ether, CH
ID: 1011477 • Letter: U
Question
Use the following information to answer questions 2 through 8:
Diethyl ether, CH3CH2OCH2CH3 ,
specific heat solid:
1.89 J/g K
heat of fusion:
7.19 kJ/mol
normal melting point:
–116.3 °C
Molar mass:
74.1 g/mole
specific heat liquid:
2.32 J/g K
heat of vaporization:
27.2 kJ/mol
normal boiling point:
34.6 °C
specific heat gas:
1.61 J/g K
3. What is the vapor pressure at 25°C?
specific heat solid:
1.89 J/g K
heat of fusion:
7.19 kJ/mol
normal melting point:
–116.3 °C
Molar mass:
74.1 g/mole
specific heat liquid:
2.32 J/g K
heat of vaporization:
27.2 kJ/mol
normal boiling point:
34.6 °C
specific heat gas:
1.61 J/g K
Explanation / Answer
At boiling point of a compound, vapour pressure of compound = atmospheric pressure = 1 atm.
For diethyl ether, boiling point = 34.6 oC
So, at T= 34.6 oC, vapour pressure of diethyl ether = 1 atm.
According to ideal gas equation, PV= nRT
So, P is directly proportional to T.
25 oC < 34.6 oC
So at 25 oC, vapour pressure of diethyl ether would be less than pressure observed at 34.6 oC.
Thus, it would be less than 1 atm.
1st option is correct.