Less. The overall equation for ATP hydrolysis can be approximated as (This is only an approximation, because the ionizedm species shown here are the major, but not the only, forms present.) Under standard conditions (i.e., [ATP] = [ADP] = [Pi] = 1 M), the concentration of water is 55 M and does not change during the reaction. Because H+ ions are produced in the reaction, at a higher [H+] (pH 5.0) the equilibrium would be shifted to the left and less free energy would be released.