Question

In thermodynamics, what are state functions?And also what is this postulate of thermodynamics for?

Answer 1

State function is used to represent thermodynamical variables that depends only on the initial and final position and does not depend on the path taken.

1. Consider three system A, B and C. If A is in thermal equilibrium with C and B is also in thermal equilibrium with C then we can say that A is in thermal equilibrium with B.

2. Conservation of energy

3. Change in entropy of an isolated system is either zero or positive during the course of time. It can not be negative. That is entropy of isolated system can never decrease with time.

4. Entropy is zero at absolute zero