scholarly journals CUBANE HEAT OF FORMATION: CALCULATION METHODS

2020 ◽  
pp. 18-24
Author(s):  
E. A. Zauer ◽  
A. B. Ershov
Keyword(s):  
Comparative Analysis ◽  
Quantum Chemistry ◽  
Molecular Mechanics ◽  
Formation Enthalpy ◽  
Heat Of Formation ◽  
Heats Of Formation ◽  
Enthalpies Of Formation ◽  
Am1 Method ◽  
Calculation Methods

A comparative analysis of the enthalpies of formation of a cubane calculated by the methods of molecular mechanics and quantum chemistry is carried out. A correlation between the experimental and calculated AM1-method values of the heats of formation of frame hydrocarbons was established, which allowed us to correct the results of calculating the heat of formation of the cubane and reduce the discrepancy with the experimental value of its formation enthalpy to 10.7 kJ / mol.

COMPARATIVE ANALYSIS OF EQUILIBRIUM BEACH PROFILE CALCULATION METHODS

2015 ◽  
pp. 39
Author(s):  
A. L. Khomchanovsky ◽  
E. A. Fedorova ◽  
An. A. Lygin ◽  
A. Sh. Khabidov
Keyword(s):  
Comparative Analysis ◽  
Calculation Methods ◽  
Beach Profile ◽  
Equilibrium Beach Profile

Calculation of the molar heat of formation of fatty acid triglycerides from the heat of combustion of vegetable oils

2021 ◽  
Vol 11 (4) ◽  
pp. 8-15
Author(s):  
Łukasz Jęczmionek
Keyword(s):  
Fatty Acid ◽  
Vegetable Oils ◽  
Calculation Method ◽  
Formation Enthalpy ◽  
Heat Of Formation ◽  
Heat Of Combustion ◽  
Calorimetric Method ◽  
Combustion Heat ◽  
Natural Oils ◽  
Fatty Acid Triglycerides

The results of the research on estimation the molar heat of formation (enthalpy) of model triglycerides found in natural oils and fats are presented. In this work a calculation method and calorimetric one were used. It was found that combustion heat values determined by separate methods are comparable; their difference was a maximum of 155 kJ/kg, and thus was significantly lower than the tolerance for the calorimetric method according to PN 86/C-04062.

scholarly journals Thermodynamics of Molybdenum Trioxide (MoO3) Encapsulated in Zeolite Y

2021 ◽  
Author(s):  
Xianghui Zhang ◽  
Andrew Strzelecki ◽  
Cody Cockreham ◽  
Vitaliy Goncharov ◽  
Houqian Li ◽  
...  
Keyword(s):  
Molybdenum Trioxide ◽  
Zeolite Y ◽  
Formation Enthalpy ◽  
Solution Calorimetry ◽  
Metal Species ◽  
Enthalpies Of Formation ◽  
Host Interactions ◽  
Oxide Melt ◽  
High Temperature Oxide ◽  
Temperature Oxide

Zeolites with encapsulated transition metal species are extensively applied in the chemical industry as heterogenous catalysts for favorable kinetic pathways. To elucidate the energetic insights into formation of subnano-sized molybdenum trioxide (MoO) encapsulated/confined in zeolite Y (FAU) from constituent oxides, we performed a systematic experimental thermodynamic study using high temperature oxide melt solution calorimetry as the major tool. Specifically, the formation enthalpy of each MoO/FAU is less endothermic than corresponding zeolite Y, suggesting enhanced thermodynamic stability. As Si/Al ratio increases, the enthalpies of formation of MoO/FAU with identical loading (5 Mo-wt%) tend to be less endothermic, ranging from 61.1 ± 1.8 (Si/Al = 2.9) to 32.8 ± 1.4 kJ/mol TO (Si/Al = 45.6). Coupled with spectroscopic, structural and morphological characterizations, we revealed intricate energetics of MoO – zeolite Y guest – host interactions likely determined by the subtle redox and/or phase evolutions of encapsulated MoO.

scholarly journals Thermodynamic properties of 5-(2-nitrophenyl) furan-2-carbaldehyde and it’s derivatives in a condensed state

2020 ◽  
Vol 3 (2) ◽  
pp. 1-6
Author(s):  
I. B. Sobechko ◽  
◽  
Yu. I. Gorak ◽  
V. M. Dibrivnyi ◽  
L. V. Goshko ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Thermodynamic Properties ◽  
Condensed State ◽  
Calculation Methods ◽  
Combustion Calorimeter

Using the precision bomb combustion calorimeter B-08-MA, the combustion energies of 5- (2- nitrophenyl) -furan-2-carbaldehyde, 5- (2-nitro-4-methylphenyl) -furan-2-carbaldehyde and 5- ( 2-nitro-4- oxymethylphenyl) -furan-2-carbaldehyde. Based on the obtained data, the values of enthalpies of combustion and formation of substances in the condensed state are calculated. A comparative analysis of experimentally determined values with theoretically calculated values by additive calculation methods is given.

scholarly journals Study of Spectroscopy and Thermodynamic Properties for Phoshours dioxide PO2 Molecular and Influence Study of Bond ( P-O ) on Spectroscopy Properties

2012 ◽  
Vol 9 (4) ◽  
pp. 616-622
Author(s):  
Baghdad Science Journal
Keyword(s):  
Free Energy ◽  
Thermodynamic Properties ◽  
Room Temperature ◽  
Formation Enthalpy ◽  
Heat Of Formation ◽  
Vibration Modes ◽  
Equilibrium Distance ◽  
Atmosphere Pressure ◽  
Gibb’S Free Energy ◽  
Good Agreement

In This research a Spectroscopic complement and Thermodynamic properties for molecule PO2 were studied . That included a calculation of potential energy . From the curve of total energy for molecule at equilibrium distance , for bond (P-O), the degenerated of bond energy was (4.332eV) instate of the vibration modes of ( PO2 ) molecule and frequency that was found active in IR spectra because variable inpolarization and dipole moment for molecule. Also we calculate some thermodynamic parameters of ( PO2 ) such as heat of formation , enthalpy , heat Of capacity , entropy and gibb's free energy Were ( -54.16 kcal/mol , 2366.45 kcal/mol , 10.06 kcal /k/mol , 59.52 kcal /k /mol, -15370.51 kcal / mol ) respectively under condition of room temperature and atmosphere pressure ( 298 k , 1 atm.). We calculate there parameters at various temperature from ( 100 – 3000 ) K . It was found that the obtainded results were in a good agreement with previous experimental facts.

Determination of the Heat of Formation of Octafluorotoluene and Calculation of D[C6F5—F] – D[C6F5—CF3]

1973 ◽  
Vol 51 (22) ◽  
pp. 3662-3664 ◽  
Author(s):  
Michael J. Krech ◽  
Stanley James W. Price ◽  
Wayne F. Yared
Keyword(s):  
Material Balance ◽  
Combustion Method ◽  
Heat Of Formation ◽  
Enthalpies Of Formation ◽  
Direct Combustion ◽  
Fold Excess

The heat of formation of octafluorotoluene has been determined using the direct combustion method previously developed for hexafluorobenzene. As in the hexafluorobenzene case the combustion of octafluorotoluene in oxygen yields CO2, CF4, and F2. With a ten-fold excess of oxygen the CO2 to CF4 ratio is 3.85 ± 0.06. A full material balance was obtained. The value of ΔHf2980(C6F5CF3,g) = −303.2 ± 1.8 kcal mol−1 may be combined with the enthalpies of formation of C6F6, CF3, and F to give D[C6F5—F] – D[C6F5—CF3] = 55.7 ± 4.0 kcal mol−1.

scholarly journals Determining efficiency of cycloid reducers using different calculation methods

2019 ◽  
Vol 290 ◽  
pp. 01008
Author(s):  
Milos Matejic ◽  
Mirko Blagojevic ◽  
Ileana Ioana Cofaru ◽  
Nenad Kostic ◽  
Nenad Petrovic ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Analytical Methods ◽  
Common Property ◽  
Experimental Results ◽  
Calculation Methods ◽  
Wide Range ◽  
Pros And Cons ◽  
Gear Trains ◽  
Central Gear ◽  
The Way

Cycloid reducers are gear trains which can be classified as planetary transmissions. These transmissions have a very wide range of uses in industry in transporters, robots, satellites, etc. This research presents a comparative analysis of three analytical methods for determining cycloid drive efficiency. The paper explores every mathematically formulated method and compares them to experimental results from literature. The presented methods for determining efficiency have a common property, in that they all determine losses due to friction on the bearing cam surface of the shaft, the rollers of the central gear and the output rollers. The calculation of efficiency values is done for standard power values. The methods differ primarily in the way they calculate losses. For each method of calculating efficiency there is an analysis of pros and cons. The paper concludes with suggestions as well as possible directions for further research.

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