The densities of and iron are 7.571 and 7.633gml1 respectively at their transformation temperature of 910C under 1 bar. The enthalpy of phase change, UH, from to is 900Jmol1 at 910C and 1665Jmol1 at 827C. Assuming that (a) trH is independent of pressure but varies linearly with temperature, and (b) the value of VV is constant, calculate the pressure under which both forms of iron coexist at 827C. (From L. S. Darken and R. D. Smith, Ind. Eng. Chem