What is entropy? Explain with examples.

Explanation

Entropy: Entropy means transformation It is denoted by 'S'.
Entropy is a measure of disorder or randomness in a system.
The greater the disorder in a system the higher is the entropy. Entropy is a state function. Entropy change `(DeltaS)` between any two states is therefore given by the equation.
`DeltaS=(q_("rev"))/(T)`
`q_("rev")` is the heat absorbed by the system isothermally and reversible at 'T' during the state change.
A substance in solid state have lowest entropy because the particles are orderly arranged. The gaseous state of the same substance have highest entropy because the particles are moving most disorderly. The liquid state of the same substance have entropy in between the values for solids and the gaseous state.
For a spontaneous process in an isolated system the change in entropy `(DeltaS)` is positive.