Thermodynamical properties of non-interacting chiral molecules are studied under the two-state model in an asymmetric double well potential. The competition between thermal effects, the tunneling process and any pseudoscalar interaction (including electroweak parity violation) is governed by a critical temperature, T-c, where the heat capacity displays a maximum, and the entropy and the population difference between left and right conformations show an inflection point. This population difference becomes appreciable at temperatures below T-c, whereas, at higher temperatures, the racemization process is more and more important. The critical values of the entropy and heat capacity are constants and independent of the chiral system under study. (C) 2009 Elsevier B. V. All rights reserved.