Engineering Thermodynamics/Third Law

Third Law of Thermodynamics The Third Law of Thermodynamics extends the definition of Entropy: Entropy is zero only in a perfect crystal at absolute zero ( 0 kelvin [- 273.15 degree Celsius ]). The Third Law of Thermodynamics can mathematically be expressed as lim ST→0 = 0 (1) where S = entropy (J/K) T = absolute temperature (K) At a temperature of absolute zero there is no thermal energy or heat. At a temperature of zero Kelvin the atoms in a pure crystalline substance are aligned perfectly and do not move. There is no entropy of mixing since the substance is pure. By -VBM