Iron (III) sulfide spherical particles (R=1 mm) are roasted at 850 C and 2 atm in air (21% oxygen) according to the reaction below. 2 Fe2S35) + 9 Ozigi = 2 Fe2O3(s) + 6 SO2(g) Assume the reaction proceeds according to the shrinking core model with constant particle size. De = 4.3 g/cm Mw=207.9 g/mol ks = 0.2 m/s De = 3x10 m/s a) Please calculate the total time for complete particle conversion. [12 pts] b) Please calculate the relative resistance of chemical reaction. [2 pts] c) If raising the temperature to 1050 C reduces the time for complete chemical reaction to 1.785 s, please estimate the activation energy for the surface reaction using rate constants (k). [6 pts) Please state all your assumptions