Synthesis and Standard Molar Formation Enthalpy of Plate Shape NaZnPO4·H2O

Plate shape NaZnPO4·H2O was synthesized by solid-state reaction at low temperature and characterized by X-Ray Diffraction, Scanning electron microscope and elemental analysis. Thermochemical study was performed with an isoperibol solution calorimeter. Based on Hess’s law, thermochemical cycl was designed to determine the dissolution enthalpies of reactants and products using a solution-reaction isoperibol calorimeter at 298.15 K, and the molar reaction enthalpy was calculated on the basis of above dissolution enthalpies. The results show that the obtained product is plate shape NaZnPO4·H2O. The standard molar formation enthalpy of the NaZnPO4·H2O is ΔfHm [NaZnPO4·H2O,s]= -1967.18 ± 0.69 kJ•mol-1.

The Studies of Assumptions Accompanying the Calibration of High-Temperature Solution Calorimeter

The Studies of Assumptions Accompanying the Calibration of High-Temperature Solution Calorimeter The main thesis of the research was the problem concerning calibration of high-temperature solution calorimeter with aluminum. The important assumptions applied at calibration of a device with aluminum were verified. Enthalpy values determined during the experiment clearly suggest that the level of deformation and diameters of aluminum samples used for calibration are negligible. The assumption that the temperature of the samples at the moment they reach the bath level is very close to room temperature, is appropriate.