Thermodynamics and Thermochemistry 1 Question 5
5. Among the following the set of parameters that represents path functions, is
(2019 Main, 9 April I) (A) $q+W$ (B) $q$ (C) $W$
(a) (A) and (D)
(b) (A), (B) and (C)
(c) (B), (C) and (D)
(d) (B) and (C)
(D) $H-T S$
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Solution:
- $q$ (heat) and $W$ (work) represents path functions. These variables are path dependent and their values depends upon the path followed by the system in attaining that state. They are inexact differentials whose integration gives a total quantity depending upon the path.
Option (a), i.e. $q+W$ and option (d), i.e. H-TS are state functions. The value of state functions is independent to the way in which the state is attained. All the state functions are exact differentials and cyclic integration involving a state functions is zero.
