Question

So the 3rd Law of Thermodynamics states: the entropy of a system approaches a constant value as the temperature approaches absolute zero.

My question is: What is the constant value?

Answer 1

As temperature approaches to absolute zero, change in entorpy approaches zero. This means system will try to attain the lowest possible energy state as temperature approcahes to absolute zero. At any give temperature, entorpy of the sytem will not be zero and hence as system try to reach to its lowest possible energy state the change in entorpy will be minimal and it will tend towards zero. As the change (S) tends to zero the entorpy of system will try to attain value of its zero energy state entropy value which is non zero quantity. And this is a constant value.

Recently, it is proved that for any process it is impossible to reduce the entropy of a system to its absolute zero value in a finite umber of operations. This constant value may be dependant on charactaristics of each individual system.