Liquid Sodium Can Be Used as a Heat Transfer Fluid

Liquid sodium can be used as a heat transfer fluid. Its vapor pressure is 40.0 torr at 633°C and 400.0 torr at 823°C. Calculate its heat of vaporization.

A) 43.4 kJ/mol
B) 52.5 kJ/mol
C) 70.6 kJ/mol
D) 1.00 × 10² kJ/mol
E) none of the above