At 373.15K and 1 atm, the molar volume of liquid water and steamare 1.88 X 10-5 m3 and 3.06 X 10-2m3, respectively. Given that the heat of vaporization ofwater is 40.79 kJ/mol, calculate the values of ?H and ?Ufor 1 mole in the following process:
H2O (l, 373.15 K, 1 atm) ---> H2O(g, 373.15 K, 1 atm)

Answer The value of and is, 40.79 kJ and 37.7 kJ respectively.

Explanation :

Heat released at constant pressure is known as enthalpy.

The formula used for change in enthalpy of the gas is:

Now we have to calculate the work done.

Formula used :

where,

w = work done  = ?

P = external pressure of the gas = 1 atm

= initial volume =

= final volume =

Now put all the given values in the above formula, we get:

Now we have to calculate the change in internal energy.

Thus, the value of and is, 40.79 kJ and 37.7 kJ respectively.

the electrical  conductivity  of asolution  of an electrolyte is measured by determining the resistance of thesolution  between two flat or cylindrical electrodes separated by a fixed distance.