text: The calculation of K at a particular temperature from a known K at another given temperature can be approached as follows if standard thermodynamic properties are available. The effect of temperature on equilibrium constant is equivalent to the effect of temperature on Gibbs energy because:
  where ΔG</sup> is the reaction standard Gibbs energy, which is the sum of the standard Gibbs energies of the reaction products minus the sum of standard Gibbs energies of reactants.
  Here, the term "standard" denotes the ideal behaviour (i.e., an infinite dilution) and a hypothetical standard concentration (typically 1 mol/kg). It does not imply any particular temperature or pressure because, although contrary to IUPAC recommendation, it is more convenient when describing aqueous systems over wide temperature and pressure ranges.
  The standard Gibbs energy (for each species or for the entire reaction) can be represented (from the basic definitions) as:
  In the above equation, the effect of temperature on Gibbs energy (and thus on the equilibrium constant) is ascribed entirely to heat capacity. To evaluate the integrals in this equation, the form of the dependence of heat capacity on temperature needs to be known.
  If the standard molar heat capacity  C can be approximated by some analytic function of temperature (e.g. the Shomate equation), then the integrals involved in calculating other parameters may be solved to yield analytic expressions for them. For example,  using approximations of the following forms:
  *For pure substances (solids, gas, liquid): 
  *For ionic species at : 
  then the integrals can be evaluated and the following final form is obtained:
  The constants A, B, C, a, b and the absolute entropy, S̆, required for evaluation of C(T), as well as the values of G and S for many species are tabulated in the literature.