What is the third law of thermodynamics

Third law of thermodynamics

The entropy of a perfect crystal is zero when the temperature of a crystal is equal to absolute zero (0 K)

• At 0 K, there is no thermal motion, and if the crystal is perfect, there will be no disorder.
• Once the temperature begins to rise above 0, the particles begin to move and entropy gradually increases as the average kinetic energy of the particles increases.
• When the temperature reaches the melting point of the substance ( T_m ), there is an abrupt increase in entropy as the substance changes from a solid to a more disordered liquid.

• Again the entropy increases gradually as the motion of the particles increases until the temperature reaches the boiling point of the substance ( T_b).
• At this point, there are other drastic increases in entropy as the substance changes from a confined liquid particle to random gas particles.