Irreversible Work and Internal Friction

The figure shows ceii as positive and dgsys as negative, so for this arrangement dwei is negative. 

On page 83 the observation was made that the work coordinate of work with a reversible limit is always a state function. Electrical woik with a galvanic cell does not contradict this statement, because the work coordinate gsys is proportional to the extent of the cell reaction, a state function. 

The thermodynamics of galvanic cells will be treated in detail in Chap. 14. 

Consider an irreversible adiabatic process of a closed system in which a work coordinate X changes at a finite rate along the path, starting and ending with equilibrium states. For a given initial state and a given change AX, the work is found to be less positive or more 

Let the work during an irreversible adiabatic process be Wirr, and the reversible adiabatic work for the same initial state and the same value of AX be Wrev- ti irr is algebraically greater than Wrev. and we can treat the difference lUirr—tt rev as excess work w x that is positive for an irreversible process and zero for a reversible process. 

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