Dissolution, integral enthalpy

Integral enthalpy of dissolution is the same as in the previous case, when one of the components is in the solid or gaseous state it depends on the composition of the solution and for dilute solutions, it approaches a certain limiting value ... 

The integral enthalpy of dissolution of H2Se04(cr) to H2Se04(aq, 1 2000) was determined as well as the enthalpies of dilution of H2Se04(aq, 1 750). The latter measurements are only presented as a small graph. As this reference may be difficult to find some enthalpies of dissolution of H2Se04(cr) estimated from the data are presented here (dilution, (H2Se04(cr), aq dilution)) kJ-mof (750, - 58.6) (1000, - 59.6) ... 

The integral enthalpies of dissolution to (CaSe04, aq 1 1600) of CaSe04 2H20(cr) and CaSe04(cr) were also measured and found to be - (8.49 + 0.21) and -(33.68 + 0.21) kJ-molrespectively. These results combine with accepted standard enthalpies of formation to Af(CaSe04 2H20, cr, 298.15 K) =... 

The authors reacted Na2Se03(cr) with a copper sulphate solution in an electrically calibrated calorimeter and measured the enthalpy change of the reaction. The product was CuSe03-2H20(cr) as shown by chemical analysis and X-ray diffraction. Crystalline anhydrous copper selenite was also prepared and the integral enthalpies of dissolution of the two selenites in 8% HMO3 (HNO3, aq 1 40, and denoted sin below) were determined. The data have been used in Table A-45 to calculate standard enthalpies of formation of the copper selenites. 

Table A-89 Integral enthalpy of dissolution of (NH4)2Se04(cr) to the standard state. The sources of the data are indicated. ...

The hydration of anhydrous magnesium nitrate evolves heat, 25,730 cal/g mole Mg(NC>3)2 — Mg(NC>3)2 6H2O (II). Likewise, the dissolution of Mg(NC>3)2 or the hydrates in water or the addition of further water to these solutions also evolves heat (12,13,14,15). Figure 4 illustrates the molar integral heat of solution of Mg(NC>3)2, the value for infinite dilution being 21,575 cal/g mole. From these figures, the enthalpies of magnesium nitrate solutions may be computed. 

Enthalpy of dissolution is the enthalpy connected with the dissolution of the given solution it depends on the composition and can be calculated from the integral dissolution enthalpies of solutions in the final and starting states ... 

Selivanova and Pakhorukov [61SEL/PAK] measured the integral heat of dissolution of H2Se03(cr), see Appendix A. The enthalpy change of ... 

It is possible to integrate the different expressions [5.11] and [5.12] if we know the variations of the enthalpies of dissolution with temperature. 

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