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Review of MgO,, Properties 3 The basic concept in thermodynamics is that these functions,which relate the beginning state and end state of a system, are not dependent on the path that the . system took in going from one state to the other. This has made thermodynamics a powerful analytical tool for the last 150 years. The equilibrium constant for a reaction is related to the standard Gibb's free energy by the formula: i RT In K = -LP [3) or K = exp (-Z�F°!RT) [4] ``here K is the equilibrium constant R is the oas constant T is the absolute temperature LSF° is the change in st_ndard free energy for the raa: ion So, for exa��ple, in equation [2], ti-he change in s`andard free enargy would be the s•`.?ndard free energy of the products minus the st-and2rd freta energy of the react=nts. The standard state adopted for reference purposes in the v-=_ bul,,, of the chemical literature is tine normal state (gas, liquid or solid) of a materia! at 208.16' (O'C), 1 atm of pressure and the normal volume of one mole of' the Su`Jst�,l��. From no,v on In this memo when I mention any of the state functions, they will all be tike functions referred to this standard state. I vJ[l use the symbol F for tine Gibb's free energy and refer to it simply as the free energy. The equilibrium con-stant K is eq--j_l to the product of tine product concentrations, i.e., K = (jN1gO2] [H20]) l ([H=021 (N1go)) [5) Notice that if the change in free energy is large 2nd negative, tine equilibrium constant will be large and positive. Thus, reactions vrith large negative free energies are frequently vrritten as in [1] rather tiinan as in [2]. When the fr:a energy is 0, the equilibrium constant is 1 and the reaction can go equally in e',Iher direction. When the free energy is positive, the reaction actually goes in the opposiie direction to that in which it is written. � Now, the free energy is defined as: • F = H-TS [3]