The vapor pressure of an unknown substance is given at various temperatures. properties of the substance are:

density of solid=1.375g/ml
density of liquid= 1.150g/ml.
freezing point= 275.0K
boiling point=375.0 K
How would i calculate the vapor pressure at 150.0K

measured at different temperatures. The following vapor pressure data are obtained. Temperature(K) Pressure mmHg 250 129.63 260 206.65 270 318.22 280 475.16 Determine the enthalpy of vaporization. I have know idea how to start this. Thank...