Karl H. Gayer

The enthalpies of solution of potassium chloride and 2-amino-2-(hydroxymethyl) 1,3-propanediol (tris)

Abstract The performance of 2-amino-2-(hydroxymethyl)-1,3-propanediol (Tris) and potassium chloride as solution calorimetry comparison standards has been evaluated. It has been established that both of these have some drawbacks, but of the two, we believe Tris is the preferable calorimeter comparison standard.

The enthalpies of formation of technetium heptaoxide and pertechnetate ion

Abstract The enthalpy of solution of Tc 2 O 7 (c) in distilled water was measured using an LKB 8700-1 solution reaction calorimeter. The value obtained is ΔH soln o (Tc 2 O 7 , c, 298.15 K) = −(45.80±1.21) kJ mol −1 . The enthalpies of solution of Tc 2 O 7 (c), Hg(l), Tc(c), and HgO(c), in an aqueous perchloric acid + ceric perchlorate solvent were also measured. These results were combined with the standard enthalpy of formation of HgO(c) from the literature to obtain the standard enthalpy of formation of Tc 2 O 7 (c). The key result of these measurements is Δ f o (Tc 2 O 7 , c, 298.15 K) = (1127.6±7.7) kJ mol −1 .

Computer analysis of resistance—time temperature—time thermograms

Abstract Two computer programs, one for the calibration experiment and the second for the reaction experiment of an isoperibol solution calorimeter have been written. The programs, written in the Fortran IV, level G language, analyze the thermograms using ( a ) a straight line approximation between the main period experimental data points, and ( b ) Dickinsons method to establish corrected temperature or resistance changes. Computer calculated values of corrected resistance changes (Δ R cor ) agree within 0.5% with the values obtained using the graphical methods of Regnault—Pfaundler and Dickinson. A program to calculate Δ H per mole has also been written.