Heat Capacities of 1-Chloroalkanes and 1-Bromoalkanes within the Temperature Range from 284.15 K to 353.15 K. A Group Additivity and Molecular Connectivity Analysis

2005 ◽  
Vol 50 (2) ◽  
pp. 619-624 ◽  
Author(s):  
Mirosław Chora̧żewski ◽  
Paweł Góralski ◽  
Mariola Tkaczyk
Keyword(s):  
Heat Capacities ◽  
Group Additivity ◽  
Connectivity Analysis ◽  
Molecular Connectivity ◽  
Temperature Range

Molar heat capacities of alkanolamines from 299.1 to 397.8 K Group additivity and molecular connectivity analyses

1997 ◽  
Vol 93 (9) ◽  
pp. 1747-1750 ◽  
Author(s):  
Yadollah Maham ◽  
Loren G. Hepler ◽  
Alan E. Mather ◽  
Andrew W. Hakin ◽  
Robert A. Marriott
Keyword(s):  
Heat Capacities ◽  
Group Additivity ◽  
Molecular Connectivity

Heat Capacities of Some Alkyl Acetates at 295-323 K

1997 ◽  
Vol 62 (10) ◽  
pp. 1527-1532 ◽  
Author(s):  
Václav Svoboda ◽  
Kornelia Gottmanová ◽  
Vladimír Hynek ◽  
Bohumír Koutek
Keyword(s):  
Experimental Data ◽  
Linear Function ◽  
Atmospheric Pressure ◽  
Heat Capacities ◽  
Group Additivity ◽  
Temperature Range ◽  
Alkyl Acetates

Molar heat capacities Cp,m at constant atmospheric pressure have been determined with a typical uncertainty of about 0.3% for eight liquid alkyl acetates H(CH2)nOCOCH3 (n = 6-12, 14), over the temperature range 295-323 K. The Cp,m values were found to be a linear function of temperature. A comparison of experimental data with those predicted by the group additivity method demonstrated a rather limited capability of the additivity scheme to predict correctly the Cp,m values for higher (n > 10) homologues in the series.

Synthesis and properties of double gadolinium tellurites

2021 ◽  
Vol 103 (3) ◽  
pp. 67-73
Author(s):  
A.A. Toibek ◽  
◽  
K.T. Rustembekov ◽  
D.A. Kaikenov ◽  
M. Stoev ◽  
...  
Keyword(s):  
Phase Analysis ◽  
Solid Phase ◽  
Heat Capacities ◽  
Ceramic Technology ◽  
Phase Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
Temperature Range ◽  
Diffraction Patterns

For the first time, double gadolinium tellurites of the composition GdMIITeO4.5 (MII — Sr, Ba) were synthesized by the solid-phase method. The solid-phase synthesis of samples was carried out from decrepitated gadolinium (III) and tellurium (IV) oxides, strontium, and barium carbonates according to the standard ceramic technology. The synthesis was carried out in the temperature range of 800-1100 °C. The samples obtained were confirmed by X-ray phase analysis. X-ray phase analysis was carried out on an Empyrean instrument in the XRDML Pananalitical format. The intensity of the diffraction maxima was estimated on a 100-point scale. X-ray diffraction patterns indexing of the powder of gadolinium tellurites — alkaline earth metals studied were carried out by the homology method. The reliability and correctness of the results of indexing the X-ray diffraction patterns are confirmed by the good agreement between the experimental and calculated values of the interplanar distances (d) and the agreement between the values of the X-ray and pycnometric densities. It was found that compounds GdSrTeO4.5 and GdBaTeO4.5 crystallize in the monoclinic system and have the unit cell parameters, namely GdSrTeO4.5 — a = 12.7610, b = 10.4289, c = 8.6235 Å, V° = 1141.83 Å3, β = 95.77°, Z = 5, ρrent. = 3.22, ρpikn. = (3.10±0.09) g/cm3; GdBaTeO4.5 — a = 15.7272, b = 15.8351, c = 7.1393 Å, V° = 1769.72 Å3, β = 95.53°, Z = 8, ρrent = 3.71, ρpick = (3.61±0.10) g/cm3. Using the Landiya method, the standard heat capacities of the compounds were estimated from the calculated values of the standard entropies, and the temperature dependences of the heat capacities of the gadolinium tellurites synthesized were determined in the temperature range of 298–850 K.

Heat capacities of O2, N2, CO, and NO at low temperatures

1969 ◽  
Vol 47 (1) ◽  
pp. 23-29 ◽  
Author(s):  
J. C. Burford ◽  
G. M. Graham
Keyword(s):  
Low Temperatures ◽  
Degrees Of Freedom ◽  
Anomalous Behavior ◽  
Heat Capacities ◽  
Temperature Range

The heat capacities of O2, N2, CO, and NO have been measured in the temperature range from 4.2 °K to about 0.8 °K. No anomalous behavior was found. The results were fitted to the Debye expression (assuming 3 degrees of freedom per molecule) to yield the following values for Θ0: O2, 104.5 ± 1.0 °K; N2, 83.5 ± 1.0 °K; CO, 103.0 ± 1.0 °K; NO, 122 ± 2 °K. The results are discussed in terms of the residual entropies of CO and NO.

Heats of vaporization and gaseous heats of formation of some five- and six-membered ring alkenes

1979 ◽  
Vol 57 (17) ◽  
pp. 2302-2304 ◽  
Author(s):  
Richard Fuchs ◽  
L. Alan Peacock
Keyword(s):  
Gas Chromatography ◽  
Double Bond ◽  
Heat Capacities ◽  
Membered Ring ◽  
Heats Of Formation ◽  
Group Additivity ◽  
Liquid Heat ◽  
Heats Of Vaporization

The heats of vaporization of 1-methylcyclopentene, 3-methylcyclopentene, ethylidenecyclopentane, 1-ethylcyclopentene, methylenecyclohexane, allylcyclopentane, vinylcyclohexane, ethylidenecyclohexane, allylcyclohexane, 3,3-diethylpentane, 2,2,4,4-tetramethylpentane, and trans-2,2,5,5-tetramethyl-3-hexene have been measured by the gas chromatography – calorimetry method. These values have been combined with previously reported liquid heats of formation to give gaseous values of ΔHf. The results indicate that the internal double bond is favored by about 0.5 kcal over the exo in both 5- and 6-membered rings, but the endo–exo differences are much smaller than previously believed. Several of the liquid heat capacities that were measured were not well predicted by group additivity schemes.

Heat capacities and thermodynamic functions of BaCuO2 in the temperature range 8–305 K

1996 ◽  
Vol 278 ◽  
pp. 1-8 ◽  
Author(s):  
Yu.F. Minenkov ◽  
N.I. Matskevich ◽  
Yu.G. Stenin ◽  
P.P. Samoilov
Keyword(s):  
Thermodynamic Functions ◽  
Heat Capacities ◽  
Temperature Range
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