Don't use steem table

The heat capacity is not constant

Use this concept

Q3: 4500kg/h of steam is fed into a turbine. The inlet temperature and pressure of 500C and 60 bar. The pressure is reduced by 50 bar and heat rate of 69.86kW is lost. If the turbine efficiency is 66.5%, Calculate, a) the exit temperature (C) if the process is assumed to be reversible adiabatic. b) the maximum possible rate of work (power, in kW ) for the process c) the actual work of the process d) the actual exit temperature (C) 5.8 Calculation of Ideal Work dtd(mS)CV=T1Qj(miS)s,+SG For completely (internally \& externally) reversible, steady-state flow process the entropy balance equation for a uniform surrounding temperature becomes: (Sm)fsTsurQ=0orQ=Tsur(mS)fs Substituting this expression for Q in the energy balance equation, i.e. [m(H+21u2+zg)]fs=Q+Ws yields: [m(H+21u2+zg)]s=Tsur(mS)fs+WS(rev)