Thermodynamics of the Solvation of Lead Nitrate in Mixed DMF-H2O Solvents at 301.15 K
Esam A. Gomaa *
Chemistry Department, Faculty of Science, Mansoura University, 35516-Mansoura, Egypt
Elsayed M. Abou Elleef
Basic Science Departments, Delta Higher Institute for Engineering & Technology, 35681- Dakhlia, Mansoura, Egypt
*Author to whom correspondence should be addressed.
Abstract
Aims: The aim of this study is to determine thermodynamic energies of the solvation of lead nitrate in mixed DMF-H2O solvents at 301.15 K. The Gibbs free energies as a very important thermodynamic property were evaluated for Pb(NO3)2 in mixed dimethylformamide DMF-H2O solvents at 301.15 K from the experimental solubility measurements. The ratio of the ionic between lead and nitrate ions was used to divide the total Gibbs free energy of the salt into its individual contribution in the mixtures used. Libration Gibbs free energy associated with moving Pb(NO3)2 in standard gas state to standard state in solution was evaluated according to specific cycle for the solvation process using the solubility product. Also the lattice energy for Pb(NO3)2 (cr) was also calculated and used for further evaluation (the symbol (cr) denotes the crystalline phase). The conventional Gibbs free energies for the cation (Pb2+) and anion (NO3-) were estimated theoretically and also the Gibbs free energy of NO3- gas was evaluated and all values were discussed.
Place and Duration of Study: Chemistry Department, Faculty of Science, Mansoura University and Basic Science Department, Delta Higher Institute for Engineering and Technology, Dalkha , Mansoura, Egypt, between June 2012 and July 2013.
Keywords: Thermodynamics, gibbs free energies, lead nitrate, solubility, solvation, aqueous and dimethylformamide