H is large enough to overcome this decrease in entropy. G o f is the standard free energy of formation. A system at constant temperature and pressure will proceed spontaneously in the direction that lowers the free energy. This is why reactions proceed to equilibrium. The equilibrium position represents the lowest free energy value available to a particular reaction system.
G is the free energy change for the reaction at specified pressures of reactants and products.
We first have to compute G o from the thermodynamic tables. Therefore the reaction is spontaneous at these pressures. You will want to know if a precipitate forms upon the addition of 5 mL each of 2M AgNO 3 and 2 M HCl. The first thing you will have to do is calculate G o from values in the table. We have doubled the volume by mixing so we have halved the concentrations of the ions.