Entropy is a property of a system which decides the quantity of conversion of heat into work. This means if the entropy of a system is more only less quantity of heat can be converted into work. Similarly if the entropy of a system is less then more quantity of heat can be converted into work.
Entropy generally denoted by “S” and specific entropy generally denoted by “s”.
SI unit of entropy – Joules/Kelvin (J/K)
SI unit of specific entropy – Joules/Kilogram-Kelvin (J/Kg-K)