Thermochemistry of the aqueous manganous ion

1969 ◽  
Vol 47 (4) ◽  
pp. 699-701 ◽  
Author(s):  
L. M. Gedansky ◽  
L. G. Hepler
Keyword(s):  
Kcal Mole ◽  
Heat Of Solution ◽  
Standard Heat ◽  
Heats Of Solution ◽  
Heats Of Dilution

Heats of solution of MnSO4(c) have been measured and combined with heats of dilution to yield ΔH0 = −15.3 kcal/mole for the standard heat of solution. This value leads to ΔHf0 = −52.9 kcal/mole for Mn2+(aq). Calculations with data from the literature give ΔGf0 = −55.1 kcal/mole for Mn2+(aq). Combination of this value with our ΔHf0 gives [Formula: see text] for Mn2+(aq). Our ΔHf0 value for Mn2+(aq) is compared with other values derived from calculations based on data taken from the literature.

Ligand field splitting energies of the hexaamminecobalt(II) ion and the hexaamminenickel(II) ion measured by a calorimetric method

1970 ◽  
Vol 48 (14) ◽  
pp. 2177-2181 ◽  
Author(s):  
Badri Muhammad ◽  
J. W. S. Jamieson
Keyword(s):  
Close Agreement ◽  
High Energy ◽  
Calorimetric Method ◽  
Ligand Field ◽  
Maximum Difference ◽  
Kcal Mole ◽  
Heat Of Solution ◽  
Field Splitting ◽  
Heats Of Solution ◽  
Splitting Energy

Various normal lower ammines and high-energy modifications of the lower ammines of cobalt(II) sulfate and nickel(II) sulfate have been prepared and the heats of solution in dilute ammonia have been measured for both types. For each of these ammine systems the maximum difference in heat of solution, expressed as kcal/mole of each heptaammine, between the high-energy and the normal salts has been found to be in close agreement with the ligand field splitting energy of the hexaamminemetal(II) ion.

Thermochemistry of Silver Bromate

1971 ◽  
Vol 49 (3) ◽  
pp. 523-524 ◽  
Author(s):  
L. M. Gedansky ◽  
L. G. Hepler
Keyword(s):  
Solubility Product ◽  
Standard Entropy ◽  
Heat Of Solution ◽  
Heats Of Solution ◽  
Calorimetric Measurements

Calorimetric measurements of the heat of solution of AgBrO3(c) in NH3(aq) have been combined with earlier data on heats of solution of AgNO3(c) in water and in NH3(aq) to yield ΔH0 = 11.78 ± 0.11 kcal mol–1 for AgBrO3(c) = Ag+(aq) + BrO3−(aq). Combination of this value with ΔG0 = 5.83 kcal mol–1 from the solubility product gives ΔS0°= 19.96 cal deg–1 mol–1 for the standard entropy of solution of AgBrO3(c) at 298 °K.

The heats of solution of alcohols in water

1969 ◽  
Vol 22 (2) ◽  
pp. 347 ◽  
Author(s):  
DM Alexander ◽  
DJT Hill
Keyword(s):  
Enthalpy Of Solution ◽  
Heat Of Solution ◽  
Quadratic Dependence ◽  
Heats Of Solution ◽  
Low Concentrations

A new calorimeter has been developed and the enthalpy of solution of methanol, ethanol, propan-1-ol, propan-2-ol, butan-1-ol, and 2- methylpropan-2-ol, in water to low concentrations, measured between 5� and 35�. In all cases, the results can be adequately represented by a quadratic dependence of heat of solution on temperature. The results have been compared qualitatively with the data for the hydrocarbons.

Calorimetrie an Ammoniumyttriumhalogeniden / Calorimetry of Ammonium Yttrium Halides

1997 ◽  
Vol 52 (3) ◽  
pp. 311-314 ◽  
Author(s):  
S. Ehrlich ◽  
H. Oppermann ◽  
C. Hennig
Keyword(s):  
Enthalpies Of Formation ◽  
Heat Of Solution ◽  
Heats Of Solution ◽  
Solid Phases

Abstract The heat of solution of all solid phases in the system YX3-NH4X with X = Cl, Br, I in 4n HX was investigated. The enthalpies of formation of the ammonium yttrium halides are derived from the enthalpies of formation of Y X3 and of NH4X and their heats of solution in An HX: ΔHB0(NH4Y2Cl7,f,298) = -561,5 ± 1,7 kcal/mol, ΔHB0((NH4)3 YCl6,f,298) = -474,5 ± 1,3 kcal/mol,ΔHB0((NH4)3YBr6,f,298) = -400,8 ± 2,6 kcal/mol, ΔHB0((NH4)3YI6,f,298) = -291,9 ± 3,0 kcal/mol.

Heats of formation of zirconium hydrides

1964 ◽  
Vol 17 (10) ◽  
pp. 1063 ◽  
Author(s):  
AG Turnbull
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Heats Of Formation ◽  
Kcal Mole ◽  
Dissociation Pressure ◽  
Heats Of Solution ◽  
Zirconium Hydrides ◽  
Zirconium Metal

Heats of solution in 3.83N HF have been measured for zirconium metal and for five zirconium hydrides to evaluate the following heats of formation AHf0298: ZrH2 -39.7, ZrH1.85 -38.2, ZrH1.70. -34.7, ZrH1.43 -30.05, ZrH1.23 -25.3 kcal/mole hydride. A review of heat capacity and entropy data for zirconium hydrides has enabled a good correlation to be made between calorimetric and dissociation pressure studies, so that the effect of composition on all thermodynamic properties is established.

The Heats of Solution and Related Thermodynamic Properties of Sodium Chlorate in Water and Water–Dioxane Mixtures

1971 ◽  
Vol 49 (2) ◽  
pp. 217-224 ◽  
Author(s):  
A. N. Campbell ◽  
O. Bhatnagar
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Activity Coefficients ◽  
Direct Method ◽  
Sodium Chlorate ◽  
Saturated Solution ◽  
Heat Of Solution ◽  
Heats Of Solution ◽  
Tentative Explanation ◽  
A Direct Method

The heats of solution of sodium chlorate in water, and in several water-dioxane mixtures, have been determined experimentally at concentrations of salt ranging from 0.01 molal to saturation. For the dilute region, a direct method was used but for the concentrated range the method was that of diluting the saturated solution. The free energy decreases due to dilution have been calculated from previously determined activity coefficients. Using these data, the entropy changes have been evaluated.The graph of heat of solution vs. concentration of sodium chlorate passes through a minimum for the solutions more concentrated in dioxane, but not for water and weak dioxane mixtures. A tentative explanation of this is offered.

The Interaction between Rubber and Liquids. 1. A Thermodynamical Study of the System Rubber-Benzene

1943 ◽  
Vol 16 (1) ◽  
pp. 89-110
Author(s):  
G. Gee ◽  
L. R. G. Treloar
Keyword(s):  
Vapor Pressure ◽  
Solution Temperature ◽  
Free Energies ◽  
Pressure Data ◽  
Heat Of Solution ◽  
Dilute Solutions ◽  
Heat Of Dilution ◽  
Vapor Pressure Data ◽  
Heats Of Dilution

Abstract Equations are developed relating the thermodynamic properties of a mixture of rubber + liquid with the vapor pressure of the liquid above the mixture. Experimental methods are described for the determination of vapor pressure over the whole range of composition of the mixture. By the use of four different methods, it was possible to measure relative vapor pressure lowerings Apo/po° from 2×10−6 to 0.997. Complete vapor pressure data are given for rubber-benzene mixtures at 25° C, together with the calculated Gibbs' free energies of dilution and solution. Temperature coefficient measurements at a number of concentrations are employed to calculate heats of dilution, and these are interpplated by a modified form of an equation due to Langmuir. In this way the heats of dilution and solution are also obtained over the whole range of composition. Combining the heat and free energy data gives the entropies of dilution and solution. The entropy of dilution is approximately twice the heat of dilution over a wide concentration range and, except in dilute solutions (< 5% rubber), both are independent of the molecular weight of the rubber. The entropy of dilution is very much larger than its ideal value, and can be approximately represented by an equation of Flory, though there are significant discrepancies in the region of dilute solutions. The molar heat of solution of rubber is so large that the miscibility of rubber and benzene can be explained only by the anomalously large entropy of solution.

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