scholarly journals CALCULATE THE STANDARD ENTHALPIES OF COMBUSTION, FORMATION AND MELTING OF THE COMPLEX ROSEOFUNGIN WITH α-, β- and γ-CYCLODEXTRIN

2021 ◽  
Vol 447 (3) ◽  
pp. 44-47
Author(s):  
R.I. Jalmakhanbetova ◽  
Ye.M. Suleimen ◽  
B.K. Kasenov
Keyword(s):  
Standard Enthalpy ◽  
Polar Compounds ◽  
Enthalpies Of Formation ◽  
Standard Enthalpy Of Formation ◽  
Chemical Thermodynamics ◽  
Enthalpy Of Combustion ◽  
Hydroxyl Groups ◽  
Initial Information ◽  
Standard Enthalpies Of Formation ◽  
Data Banks

One of the most important quantities in chemical thermodynamics and thermochemistry is the enthalpy of combustion. Of the currently existing methods for calculating the heat of combustion of natural and synthetic organic compounds, the most acceptable and correct in our case was the Karash method. In this study, the standard enthalpy of combustion, the standard enthalpy of formation, and the melting enthalpy of the antibiotic roseofungin and its cyclodextrin derivatives were calculated. As a result of the study, the thermodynamic constants of the standard enthalpies of combustion, standard enthalpies of formation, and the enthalpies of melting of the above compounds were calculated, which are of interest for physicochemical modeling of processes with their participation, serve as initial information arrays for loading into fundamental thermodynamic data banks and reference books, and is also important for standardization and certification of these complexes. It should be noted that the presence of a large number of hydroxyl groups in the structures of the studied complexes allows them to be attributed to polar compounds.

Calorimetric determination of the enthalpy of formation of InN and comparison with AlN and GaN

2001 ◽  
Vol 16 (10) ◽  
pp. 2824-2831 ◽  
Author(s):  
M. R. Ranade ◽  
F. Tessier ◽  
A. Navrotsky ◽  
R. Marchand
Keyword(s):  
Enthalpy Of Formation ◽  
Standard Enthalpy ◽  
Sodium Molybdate ◽  
Solution Calorimetry ◽  
Large Error ◽  
Area Measurement ◽  
Enthalpies Of Formation ◽  
Standard Enthalpy Of Formation ◽  
Straight Line ◽  
The Enthalpy Of Formation

The standard enthalpy of formation of InN at 298 K has been determined using high-temperature oxidative drop solution calorimetry in a molten sodium molybdate solvent at 975 K. Calorimetric measurements were performed on six InN samples with varying nitrogen contents. The samples were characterized using x-ray diffraction, chemical analysis, electron microprobe analysis, and Brunauer–Emmett–Teller surface area measurement. The variation of the enthalpy of drop solution (kJ/g) with nitrogen content is approximately linear. The data, when extrapolated to stoichiometric InN, yield a standard enthalpy of formation from the elements of ?28.6 ± 9.2 kJ/mol. The relatively large error results from the deviation of individual points from the straight line rather than uncertainties in each set of data for a given sample. This new directly measured enthalpy of formation is in good agreement with the old combustion calorimetric result by Hahn and Juza (1940). However, this calorimetric enthalpy of formation is significantly different from the enthalpy of formation values derived from the temperature dependence of the apparent decomposition pressure of nitrogen over InN. A literature survey of the enthalpies of formation of III–N nitride compounds is presented.

scholarly journals Thermochemistry of the lower bromides of tantalum

1980 ◽  
Vol 58 (9) ◽  
pp. 938-941 ◽  
Author(s):  
Alan D. Westland
Keyword(s):  
Enthalpy Of Formation ◽  
Standard Enthalpy ◽  
Solution Calorimetry ◽  
Heat Capacities ◽  
Enthalpies Of Formation ◽  
Standard Enthalpy Of Formation

The standard enthalpy of formation of tantalum(IV) bromide has been determined by solution calorimetry: ΔHf0(TaBr4(c) 298 K) = −125.6 ± 0.5 kcal mol−1. Experimental estimates of the enthalpies of formation of tantalum(III) bromide and tantalum(II,III) bromide were also obtained. Estimates of the entropies and heat capacities of the compounds are also given.

Thermochemical study of adducts of methylurea with zinc, cadmium, and mercury halides

1982 ◽  
Vol 60 (16) ◽  
pp. 2132-2136 ◽  
Author(s):  
Claudio Airoldi ◽  
Aécio P. Chagas ◽  
Francisco P. Assunção
Keyword(s):  
Standard Enthalpy ◽  
Enthalpies Of Formation ◽  
Enthalpy Of Sublimation ◽  
Thermochemical Study ◽  
Enthalpies Of Solution ◽  
Metal Halides ◽  
Enthalpies Of Dissolution ◽  
Zinc Cadmium ◽  
Standard Enthalpies Of Formation

The adducts Zn(mu)2X2 (X = Cl, Br), M(mu)X, (M = Cd, Hg and X = Cl, Br) have been characterized. The CO and NH stretching frequencies indicate that methylurea (mu) is bound to metals through oxygen. Enthalpies of dissolution of the adducts in ethanol or methanol have been measured calorimetrically. Combination with the enthalpies of solution of metal halides and ligand in the same solvents at 298.15 K yielded the standard enthalpy [Formula: see text] for the reaction: MX,(s) + nmu(s) → M(mu)nX2, (s): Zn(mu)2Cl2, (−36.27±0.51); Zn(mu)2Br2, (−37.52±0.97); Cd(mu)Cl2, (−22.78±0.26); Cd(mu)Br2, (−9.58±0.26); Hg(mu)Cl2, (−13.91±0.41);and Hg(mu)Br2,(−13.29±0.48). The standard enthalpies of formation of the adducts in the same sequence as above, [Formula: see text] (s, 298.15 K): −1024, −938, −701, −612, −524, and −470 kJ mol−1, were determined from these values, the standard enthalpy of the ligand (−285 ± 15 kJ mol−1) being obtained via combustion calorimetry, and literature values of the standard enthalpies of metal halides being used. With the determination of the standard enthalpy of sublimation of the ligand (78.2 kJ mol−1) it was possible to determine the standard enthalpies of the reactions MX2(g) + nmu(g) → M(mu)X2 (s) and M(mu)nX2 (s) → MX2 (s) + nmu(g). The enthalpies of metal–oxygen bonds were also estimated.

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