Journal Articles (before-1995)

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    Ionic Product and Enthalpy of Ionization of Water from Electromotive Force Measurements
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (11), 1977) Covington, Arthur K; Ferra, M. Isabel A; Robinson, Robert A
    New e.m.f. data have been obtained for the cell: Pt, H2|MOH,NX|AgX|Ag at 25°C where M, N = Li, Na, K, Cs and X = Cl, Br, from which the ionic product (Kw) of water can be obtained (pKw= 14.004). Application of a theory of mixed electrolyte solutions to the results enables the variation of the apparent ionic product (K′w) with ionic strength and cation to be expressed in terms of the properties of the pure alkali metal halide and hydroxide solutions at the same total ionic strength. The conditions M = Li, N = K, X = Cl were selected for a study over the temperature range 0–60°C and from these measurements the enthalpy of ionization of water was calculated (ΔH°= 13430 ± 5 cal mol–1). The use of mixed cations in the cell minimises the variation of apparent ionic product with ionic strength, thereby reducing the uncertainty in the extrapolation to zero ionic strength felt previously to be the principal contributing factor leading to the discrepancy between calorimetric and e.m.f. derived values for the ionization enthalpy of water.
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    Solute-Solvent Interaction in Water+t-Butylalcohol Mixtures Part 9.—Enthalpies of Transfer for KBr, KI, HBr and HI1
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (12), 1977) Pointud, Yvon; Juillard, Jean
    Enthalpies of transfer of HI, HBr, KI and KBr from water to water + TBA mixtures, which have been obtained from calorimetric measurements, are reported. Gibbs free energies and entropies of transfer are calculated from previous data. The solvation of these electrolytes in water + TBA media is thus discussed in relation to the structure of the mixtures with special reference to the Atkinson's model of fluctuating cages.
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    Thermodynamic Properties of Hydrogen in Palladium and its Alloys under Conditions of Constant Volume
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1977, 73 (07), 1977) Oates, W. Alan; Flanagan, Ted B
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    Thermodynamic study of disorder in mercury(II) diamminodichloride and mercury(II) diamminodibromide
    (Journal of the Chemical Society : Faraday Transaction - I. The Chemical Society, London. 1978, 74 (09-12), 1978) Cooke, Michael D.; Linford, Roger G.; Staveley, Lionel A. K.; Worswick, Richard D.
    In the salts mercury(II) diammino-dichloride and -dibromide the mercury atoms are positionally disordered at room temperature, the disorder being tantamount to that of dimers (the linear NH3—Hg—NH2+3 cations) on a cubic lattice. The heat capacity of the chloride has been measured from 3 to 300 K and that of the bromide from 10 to 300 K, giving the apparent (calorimetric) entropies of the salts at 298.15 K. The true (equilibrium) entropies at the same temperature have been determined by e.m.f. measurements on cells incorporating the complexes in the cell reaction, combined with previous measurements of the heat of solution of gaseous ammonia in the electrolytes used in the cells. A comparison of the entropy values shows that both salts retain entropy, and hence are still disordered, at the absolute zero. The value of the residual entropy for the chloride (considered to be the more accurate of the two) is 12.0 ± 3.0 J K–1 mol–1, and that for the bromide is 20.0 ± 7.5 J K–1 mol–1. These estimates of the residual entropy are briefly considered in the light of theoretical work on the disordered dimer problem. It seems likely that the residual entropy due to the disordered arrangement of the cations is supplemented by some degree of (possibly consequential) orientational disorder of the ammonia molecules.