O=C(NCC(=O)N1CC(O)CC1C(=O)N1CC(O)CC1C(=O)OCc1ccccc1)OCc1ccccc1
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?