THERMOCHEMISTRY OF ULEXITE

Authors
CHEN RY LI J XIA SP GAO SY
Citation
Ry. Chen et al., THERMOCHEMISTRY OF ULEXITE, Thermochimica acta, 306(1-2), 1997, pp. 1-5
Citations number
13
Journal title
Thermochimica acta → ACNP
ISSN journal
00406031
Volume
306
Issue
1-2
Year of publication
1997
Pages
1 - 5
Database
ISI
SICI code
0040-6031(1997)306:1-2<1:>2.0.ZU;2-O
Abstract
The enthalpy of solution of ulexite NaCa[B5O6(OH)(6)]5 . H2O in approx imate to 1 mol dm(-3) aqueous hydrochloric acid has been measured. Fro m this result and the enthalpies of solution of H(3)BO(0)3 in HCl(aq), of CaO in aqueous (hydrochloric acid + boric acid), and of NaCl in aq ueous (hydrochloric acid + boric acid + calcium oxide), the standard m olar enthalpy of formation of ulexite of -6762.24 +/- 4.22 kJ mol(-1) has been obtained. The standard molar entropy of formation of ulexite was calculated from the thermodynamic relation with the standard molar Gibbs free energy of formation of ulexite computed from its solubilit y in water. (C) 1997 Elsevier Science B.V.