Which of the following is/are state function/functions?
- 1. q+w
- 2. q
- 3. w
- 4. H-TS
Select the correct answer using the code given below.
1 and 4 only
1, 2 and 4
2, 3 and 4
1 only
Answer is Right!
Answer is Wrong!
This question was previously asked in
UPSC CDS-1 – 2019
1. q+w: According to the first law of thermodynamics, $\Delta U = q+w$, where U is internal energy. Internal energy (U) is a state function, so the change in internal energy ($\Delta U$) is also a state function. Thus, q+w represents $\Delta U$ and is a state function.
2. q: Heat (q) is a path-dependent quantity; the amount of heat transferred depends on the process followed.
3. w: Work (w) is a path-dependent quantity; the amount of work done depends on the process followed.
4. H-TS: This expression is the definition of Gibbs Free Energy (G). Gibbs Free Energy (G) is a state function, as it is defined in terms of state functions (Enthalpy H, Temperature T, and Entropy S).
Therefore, q+w and H-TS are state functions.
– Internal energy ($\Delta U = q+w$) is a state function.
– Gibbs Free Energy ($G = H-TS$) is a state function.
– Heat (q) and Work (w) are path functions.