25. Solving a chemistry problem

3. For pure ammonia, the temperature dependences of saturated vapor pressure are known at equilibrium liquid-vapor and crystal-vapor
Vapor crystals T,c 166.6 175.7 181.3 187.4 194.0
R,Pa 181 667 1333 2666 5333
Liquid-steam Т,к 198.9 208.3 216.2 222.2 232.6
R,Pa 7999 18033 26660 40134 73130
At the triple point, the mass densities in the liquid and crystalline states are 817 and 827 kg/m3, respectively. Plot the saturation vapor pressure versus temperature P=f(T) and lnP=f(1/T)/. Determine the coordinates of the triple point.
Graphic molar heats of evaporation and sublimation, assuming that they do not depend on temperature. Determine the molar heat of fusion. Find Tmelt of the substance at p=8*107 Pa.