Question No 33 A sphere of densely compacted NiO is reduced in pure H2 with the formation of a porous nickel product having the same external radius RO as the original sphere. Suppose that the system exhibits "mixed control by gaseous transport through the product layer and a chemical reaction at the reaction interface. Derive expressions to describe the progress of the reaction as a function of time. Define all the necessary physical properties and rate constants carefully. State all If you obtained a graph of sample weight versus time in the laboratory, how would you analyse the data to teat your model; i.e. what type of coordinates would you cry in a modified graph? pressure of hydrogen to the equilibrium amount of hydrogen in solid solution in palladiu in Neutron diffraction shows that hydrogen dissolves in the octahedral sites of fcc palladio Assuming only nearest neighbor interaction between the hydrogen atoms in solution, relate the 8丌2AT mkt The rotational partition function is the translational (Pf) 2h h vibrational (Pf) hy exp Use the canonical ensemble or the grand canonical ensemble. Compute the critical temperature. Tc and composition Ac, for phase separation. Sketch the pressure-composition isotherm for T>Tc T=Tc and T<Tc. What is the sign of the interaction parameter WHH for phase separation? Question No 35 Consider the solidification of an alloy of composition Co indicated on the phase diagram below: t Where ml =slope of the liquidus and K= equilibrium distribution coefficient= CS/CL (a) Using the phase diagram data and assuming steady state growth conditions and equilibrium partitioning, develop the stability relation for planar front growthQuestion No. 33 A sphere of densely compacted NiO is reduced in pure H2 with the formation of a porous nickel product having the same external radius R0 as the original sphere. Suppose that the system exhibits “mixed control” by gaseous transport through the product layer and a chemical reaction at the reaction interface. Derive expressions to describe the progress of the reaction as a function of time. Define all the necessary physical properties and rate constants carefully. State all assumptions. If you obtained a graph of sample weight versus time in the laboratory, how would you analyse the data to teat your model; i.e. what type of coordinates would you cry in a modified graph? Question No. 34 Neutron diffraction shows that hydrogen dissolves in the octahedral sites of fcc palladium. Assuming only nearest neighbor interaction between the hydrogen atoms in solution, relate the pressure of hydrogen to the equilibrium amount of hydrogen in solid solution in palladium. The rotational partition function is 2 2 2 8 h π AkT , the translational (Pf) = 2 3 2 2 2 V h mkT ⎟ ⎟ ⎠ ⎞ ⎜ ⎜ ⎝ ⎛ π and the vibrational (Pf) = ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ −− ⎟ ⎠ ⎞ ⎜ ⎝ ⎛ − kT hv kT hv exp1 2 exp . Use the canonical ensemble or the grand canonical ensemble. Compute the critical temperature. Tc, and composition θc , for phase separation. Sketch the pressure-composition isotherm for T>Tc; T=Tc and T<Tc. What is the sign of the interaction parameter WHH for phase separation? Question No. 35 Consider the solidification of an alloy of composition Co indicated on the phase diagram below: Where mL = slope of the liquidus and K = equilibrium distribution coefficient = CS/CL (a) Using the phase diagram data and assuming steady state growth conditions, no mixing and equilibrium partitioning, develop the stability relation for planar front growth