Differential Temperature Modelling (DTM) for the Determination of Molecular Masses of Strong Acids (Per Chloric and Sulphuric Acids)

Abstract

The molecular masses of two (2) strong acids: per chloric (HClO 4 ) and sulphuric (H 2 SO 4 ) have been determined using an experimental guided thermochemical model. The exothermic spree of strong acids was exploited at various percentage dilutions ranging from 10% to 50% using standard procedures. The differential temperature, ?T and other thermochemical parameters (basic constants, kb 2 and thermohydrobasic constants, ?T- 18kb 3 ) were measured and theoretically manipulated. The ?T (HClO 4 ) / o C: 6.0, 11.0, 18.0, 22.0, 27.0 and ?T (H 2 SO 4 ) / o C: 20.0, 48.5, 56.0, 72.0, 84.0 at constant pressure and volume, showed a steady increase in differential temperature within the percentage dilution range. The basic constants: 0.051, 0.093, 0.152, 0.185, 0.228 were obtained for per chloric acid and 0.149, 0.361, 0.417, 0.536, 0.625 were obtained for sulpuric acid at constant pressure and volume. The thermohydrobasic constants: 5.082, 9.326, 15.264, 18.670, 22.896 were obtained for per chloric acid and 14.643, 35.509, 41.001, 52.716, 61.501 were obtained for sulphuric acid at constant pressure and volume. The inverse of the gradient of the plot of basic constants, Kb 2 versus thermohydrobasic constants, ?T – 18Kb 3 affords the molecular masses of 101.00±0.51 a.m.u and 98.04±0.04 a.m.u for per chloric acid and sulphuric acid respectively.