Page 175 - Advanced thermodynamics for engineers
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7.7 PROBLEMS       161





                                      vc p                                                  <T
                    What is the value of    of a gas which obeys the Clausius equation of state, p ¼  ?
                                       vp                                                 v m   b
                                           T
               P7.3 Show that if the ratio of the specific heats is 1.4, then


                                                 vp     7 vp
                                                      ¼         :
                                                 vT     2 vT
                                                     s         v

               P7.4 Show that


                                                                         !
                                                     vðf=TÞ      vðg=TÞ
                                      ðaÞ h   u ¼ T 2
                                                       vT         vT
                                                            v           p
                                                      ,
                                                   2        2
                                           c p   v g       v f
                                        ðbÞ  ¼     2         2  :
                                           c v   vT       vT
                                                      p        v
               P7.5 Show


                                                           vv
                                         ðaÞ Tds ¼ c p dT   T  dp
                                                           vT
                                                              p

                                                     vT          vT
                                         ðbÞ Tds ¼ c v   dp þ c p    dv
                                                     vp          vv
                                                        v           p

                                          vh            vv
                                      ðcÞ      ¼ v   T      :
                                          vp            vT
                                              T            p
               P7.6 Show that, for a pure substance,



                                           vs       vs      vs    vv
                                                ¼        þ
                                           vT       vT      vv    vT
                                               p       v       T      p
                    and from this, prove that

                                                        vp    vv
                                             c p   c v ¼ T         :
                                                        vT    vT
                                                            v     p
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