Third Law of Thermodynamics
Third Law of Thermodynamics: Overview
This topic covers the concept of Third Law of Thermodynamics.
Important Questions on Third Law of Thermodynamics
Identify the correct statement regarding entropy:

What is residual entropy of the substance?

Calculate the entropy change for the following reaction at and pressure.
, the absolute entropy values () for and .

Write the statement of third law of thermodynamics.

Third law of thermodynamics helps in the calculation of the absolute entropy of a substance at any temperature ‘’.

The third law of thermodynamics states that, the entropy of a perfect crystal at a temperature of zero degree Celsius is equal to zero.

Write statement for the law of thermodynamics?

At what temperature is the entropy of a perfectly crystalline substance taken as zero?

State the third law of thermodynamics.

Why is it impossible for any substance to have an absolute entropy zero at temperature greater than ?

State third law of thermodynamics. What is its usefulness?

Which of the following allotropes of sulphur has maximum at ?

Among the following, the reaction that is accompanied by a decrease in the entropy is

Identify the correct statement regarding entropy.

Entropy is a measure of disorder. For perfect crystalline substances at , entropy becomes:

For a perfectly crystalline solid Cp,m = aT3 , where 'a' is constant. If Cp,m is at 10 K, molar entropy at 20 K is :

Which law of thermodynamics help in calculating entropy at different temperatures?

The entropy of a perfectly crystalline material is zero at . This statement matches with the-

The entropy of a perfectly crystalline material is zero at 0 K. This is statement of
