Page 104 - Modeling of Chemical Kinetics and Reactor Design
P. 104

74    Modeling of Chemical Kinetics and Reactor Design

                                Since the order of differentiating is indifferent, then


                                                ∂ 
                                  ∂µ          V
                                   i      =           = V i                          (2-79)
                                  ∂ 
                                                ∂ 
                                  P            n
                                       ,
                                         i ,
                                                     ,,
                                      Tn n j      i  TPn j
                              and similarly
                                  ∂µ i        −∂  S
                                          =             =− S i                         (2-80)
                                                ∂ 
                                  ∂ 
                                  T           n    ,,
                                         i ,
                                       ,
                                      Pn n j        TPn j
                                Substituting Equation 2-80 into Equation 2-74 gives
                                              ∂ µ 
                                 µ  =  H +  T   i                                      (2-81)
                                  i     i      ∂ T 
                                                      i ,
                                                    ,
                                                   Pn n j
                                Rearranging Equation 2-81 yields

                                  ∂  µ i  
                                    T         −H i                                   (2-82)
                                             =    2
                                   ∂T            T
                                       
                                          ,
                                           i ,
                                         Pn n j
                                           EFFECT OF TEMPERATURE ON
                                           THE EQUILIBRIUM CONSTANT

                                Generally,

                                         ∑  υµ  o  
                                        
                                         −
                                                  
                                 K = exp      i                                        (2-83)
                                           RT    
                                                  
                                        
                              or

                                 ln K =  −1 ∑  υµ o                                      (2-84)
                                              i
                                        R      T
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