Evaluation of Ideal Work the General Expression

We will demonstrate next that evaluation of the ideal work for a given process can be accomplished using the properties of the system in its initial and final states only, namely without resorting each time to the development of a hypothetical reversible process, as it was done in Example 5,1. 

Application of the first law to this ideal (reversible) process yields  

Since this reversible operation effects the same change in the system as the real process  

To develop an expression for Qiid), also in terms of the system properties, we note that  

for a flow process - the typical case in practice - involving a change of a given system from state 1 to state 2, Eq.5.3.2 allows the evaluation of the ided work from the initial and final properties of the system only. 

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