//Chapter-4,Example 8,Page 94 clc; close; delta_H_C= -393 // enthalpy for carbon delta_H_H2= -286 //enthalpy for hydrogen delta_H_C3H8=-2220 //enthalpy for propane // According to Hess's Law... delta_H1 = delta_H2 - delta_H3 //delta_H2 for reaction... 3C +4H2 +5O2 ----> 3CO2 +4H2O delta_H2= 3*delta_H_C +4*delta_H_H2 //delta_H2 for reaction... C3H8 + 5O2 ----> 3CO2 +4H2O delta_H3= delta_H_C3H8 delta_Hf= delta_H2 - delta_H3 //enthalpy for propane at 298 K printf('the enthalpy of formation of propane at 298K is %.f Kcal', delta_Hf)