We have measured the densities of aqueous solutions of glycine, glycine plus equimolal HCl, and glycine plus equimolal NaOH at temperatures 278.15 <= T/K <= 368.15, molalities 0.01 <= m/mol . kg(-1) <= 1.0, and at p = 0.35 MPa, using a vibrating tube densimeter. We have also measured the heat capacities of these solutions at 278.15 <= T/K <= 393.15 and at the same in and p using a fixed-cell differential scanning calorimeter. We used the densities to calculate apparent molar volumes V-phi and the heat capacities to calculate apparent molar heat capacities C-p.phi for these solutions. We used our results and values of V-phi(T,m) and C-p,C-phi(T,m) for HCl(aq), NaOH(aq), NaCl(aq) from the literature to calculate parameters for Delta C-r(p.m)(T,m) for the first and second proton dissociations from protonated aqueous cationic glycine. We then integrated this value of Delta C-r(p,m)(T,m) in an iterative algorithm, using Young's Rule to account for the effects of speciation and chemical relaxation on the observed V-phi and C-p,C-phi of the solutions. This procedure yielded parameters for V-phi(T, m) and C-p,C-phi(T, m) for glycinium chloride {H(2)Gly(+)Cl(-)(aq)} and sodium glycinate {Na(+)Gly(-)(aq)} which successfully modeled our observed results. We have then calculated values of Delta C-r(p,m), Delta H-r(m), Delta V-r(m), and pQ(a) for the first and second proton dissociations from protonated aqueous glycine as functions of T and m. (C) 2005 Elsevier Ltd. All rights reserved.