For an enzymatic reaction, a biochemist at UC Davis has determined a standard enthalpy of -10.5kJ/mol and a standard entropy of +2 J/mol. When he measured the concentration of products and reactants (not at equilibrium) under the conditions of human body temperature as 2 micromoles of products and 17.3 micromoles of substrates, what was the current free energy difference at that point of the reaction?