Consider the following series of elementary steps for the reaction A+BC+D: 1. A(g) + A* 2....

 

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Consider the following series of elementary steps for the reaction A+BC+D: 1. A(g) + A* 2. B(g)** B** 3. A*+ B** C(g)+D(g) +*+** Where steps 1 and 2 are quasi-equilibrated and step 3 is irreversible. There are two discrete types of sites* and **, each with there own site balance. Assume there is a distribution of sites for adsorption of A (on sites *), but not for adsorption of B (on sites **), and that the enthalpy for adsorption of A has varied enthalpy of adsorption: Q1 = Q0,1(1 - 1*0A) (a) Show that the coverage of A on sites * would be similar for a system of sites with constant enthalpy of adsorption (a Langmuirian surface), and determine what Q would be for that Langmuirian surface (using SOLVER in Excel, or another non-linear regression program). Plot the predicted Temkin and Langmuir isotherms for species A in the pressure range 0.1-3 bar at 600 K. (b) Plot the max percent deviation between the two models (in this range of PA) as a function of 1, for values of a between 0.3 and 0.9 (choose values of a spaced by 0.1). How high can ai become while keeping the deviation between the two predictions below 25%? Is the deviation worse for higher or lower values of 1, and how do you explain this trend? (c) Plot the Langmuir isotherm for species B in the pressure range 0.1-3 bar at 600 K. (d) Plot the coverages of species A and species be at a pressure of 1 bar A and 1 bar B, as a functions of temperature, from 600-800 K. (e) Does the rate of the reaction increase with temperature as temperature is increased from 600- 800 K? Why or why not? Assume: Q0,160,000 J mol-1 Q2 80,000 J mol-1 = 0.3 K = Ko,1*exp(Q1/RT) bar K2 K0,2*exp(Q2/RT) bar K3=1013*exp(-100,000/RT) s 10-5 bar-1 K0,1 K0,2 = 10-6 bar- [L]= 10-11 mol m T = 600 K Recall: For the Temkin isotherm: In Ko,1e Qo1/RT PA Consider the following series of elementary steps for the reaction A+BC+D: 1. A(g) + A* 2. B(g)** B** 3. A*+ B** C(g)+D(g) +*+** Where steps 1 and 2 are quasi-equilibrated and step 3 is irreversible. There are two discrete types of sites* and **, each with there own site balance. Assume there is a distribution of sites for adsorption of A (on sites *), but not for adsorption of B (on sites **), and that the enthalpy for adsorption of A has varied enthalpy of adsorption: Q1 = Q0,1(1 - 1*0A) (a) Show that the coverage of A on sites * would be similar for a system of sites with constant enthalpy of adsorption (a Langmuirian surface), and determine what Q would be for that Langmuirian surface (using SOLVER in Excel, or another non-linear regression program). Plot the predicted Temkin and Langmuir isotherms for species A in the pressure range 0.1-3 bar at 600 K. (b) Plot the max percent deviation between the two models (in this range of PA) as a function of 1, for values of a between 0.3 and 0.9 (choose values of a spaced by 0.1). How high can ai become while keeping the deviation between the two predictions below 25%? Is the deviation worse for higher or lower values of 1, and how do you explain this trend? (c) Plot the Langmuir isotherm for species B in the pressure range 0.1-3 bar at 600 K. (d) Plot the coverages of species A and species be at a pressure of 1 bar A and 1 bar B, as a functions of temperature, from 600-800 K. (e) Does the rate of the reaction increase with temperature as temperature is increased from 600- 800 K? Why or why not? Assume: Q0,160,000 J mol-1 Q2 80,000 J mol-1 = 0.3 K = Ko,1*exp(Q1/RT) bar K2 K0,2*exp(Q2/RT) bar K3=1013*exp(-100,000/RT) s 10-5 bar-1 K0,1 K0,2 = 10-6 bar- [L]= 10-11 mol m T = 600 K Recall: For the Temkin isotherm: In Ko,1e Qo1/RT PA