scholarly journals On the Determination of Molar Heat Capacity of Transition Elements: From the Absolute Zero to the Melting Point

2021 ◽  
Author(s):  
Ivaldo Leão Ferreira ◽  
José Adilson de Castro ◽  
Amauri Garcia
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Molar Heat Capacity ◽  
Materials Science ◽  
Solid Phase ◽  
Transition Elements ◽  
Phase Nucleation ◽  
New Formulation ◽  
Solid Liquid

Molar specific heat is one of the most important thermophysical properties to determine the sensible heat, heat of transformation, enthalpy, entropy, thermal conductivity, and many other physical properties present in several fields of physics, chemistry, materials science, metallurgy, and engineering. Recently, a model was proposed to calculate the Density of State by limiting the total number of modes by solid–liquid and solid–solid phase nucleation and by the entropy associated with phase transition. In this model, the new formulation of Debye’s equation encompasses the phonic, electronic, and rotational energies contributions to the molar heat capacity of the solids. Anomalies observed in the molar specific heat capacity, such as thermal, magnetic, configurational transitions, and electronic, can be treated by their transitional entropies. Model predictions are compared with experimental scatter for transitional elements.

Thermochemistry

2009 ◽  
Author(s):  
Christopher O. Oriakhi
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Temperature Change ◽  
Chemical Reactions ◽  
Molar Heat Capacity ◽  
Physical Object ◽  
Heat Energy ◽  
Chemical Bonds ◽  
Quantity Of Heat

All chemical reactions involve energy changes. Some reactions liberate heat to the surroundings; others absorb heat from the surroundings. The breaking of chemical bonds in reactants and the formation of new ones in the products is the source of these energy changes. Calorimetry is the experimental determination of the amount of heat transferred during a chemical reaction. This measurement is carried out in a device called a calorimeter, which allows all the heat entering or leaving the reaction to be accounted for. This is done by observing the temperature change within the calorimeter as the reaction takes place; if we know how much energy is needed to change the calorimeter’s temperature by a given amount, we can calculate the amount of energy involved in the reaction. The relation between energy and temperature change for the calorimeter or for any other physical object is known as its heat capacity (C), which is the amount of heat energy required to raise the temperature of that object by 1°C (or 1 K). This can be expressed in mathematical terms as: C = q/ΔT where q is the quantity of heat transferred and ΔT is the change in temperature, calculated as ΔT = Tf − Ti. The larger the heat capacity of a body, the larger the amount of heat required to produce a given rise in temperature. The heat capacity of 1 mol of a substance is known as the molar heat capacity. Also, the heat capacity of 1 g of a substance is known as the specific heat . To determine the specific heat of a substance, measure the temperature change, ΔT, that a known mass, m, of a substance undergoes as it gains or loses a known quantity of heat, q. That is: Specific heat (c) = Quantity of heat gained or lost/Mass of substance (in grams)×Temperature change (ΔT) or c = q/m×ΔT The unit of specific heat is J/g-K or J/g°C.

Heat capacities and enthalpies of fusion and transformation for solvates of some salts with dimethyl sulfoxide and dimethylformamide

1988 ◽  
Vol 53 (12) ◽  
pp. 3072-3079
Author(s):  
Mojmír Skokánek ◽  
Ivo Sláma
Keyword(s):  
Heat Capacity ◽  
Phase Transformation ◽  
Phase Transformations ◽  
Dimethyl Sulfoxide ◽  
Liquidus Temperature ◽  
Molar Heat Capacity ◽  
Solid Phase ◽  
Zinc Nitrate ◽  
Heat Capacities ◽  
Liquid Phases

Molar heat capacities and molar enthalpies of fusion of the solvates Zn(NO3)2 . 2·24 DMSO, Zn(NO3)2 . 8·11 DMSO, Zn(NO3)2 . 6 DMSO, NaNO3 . 2·85 DMSO, and AgNO3 . DMF, where DMSO is dimethyl sulfoxide and DMF is dimethylformamide, have been determined over the temperature range 240 to 400 K. Endothermic peaks found for the zinc nitrate solvates below the liquidus temperature have been ascribed to solid phase transformations. The molar enthalpies of the solid phase transformations are close to 5 kJ mol-1 for all zinc nitrate solvates investigated. The dependence of the molar heat capacity on the temperature outside the phase transformation region can be described by a linear equation for both the solid and liquid phases.

Determination of the specific heat capacity of healthy and tumorous human tissue

1995 ◽  
Vol 251 ◽  
pp. 199-205 ◽  
Author(s):  
K. Giering ◽  
I. Lamprecht ◽  
O. Minet ◽  
A. Handke
Keyword(s):  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Human Tissue

scholarly journals Высокотемпературная теплоемкость германатов Pr-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- и Nd-=SUB=-2-=/SUB=-Ge-=SUB=-2-=/SUB=-O-=SUB=-7-=/SUB=- в области 350-1000 K

2018 ◽  
Vol 60 (3) ◽  
pp. 618
Author(s):  
Л.Т. Денисова ◽  
Л.А. Иртюго ◽  
В.В. Белецкий ◽  
Н.В. Белоусова ◽  
В.М. Денисов
Keyword(s):  
Differential Scanning Calorimetry ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Temperature Effect ◽  
Molar Heat Capacity ◽  
Solid Phase Synthesis ◽  
Solid Phase ◽  
Scanning Calorimetry ◽  
Phase Synthesis

AbstractPr2Ge2O7 and Nd2Ge2O7 were obtained via solid-phase synthesis from Pr2O3 ( Nd2O3 ) and GeO2 with multistage firing in air within 1273–1473 K. A temperature effect on molar heat capacity of the oxide compounds was measured with a differential scanning calorimetry. Their thermodynamic properties were calculated from the C _ P = f ( T ) dependences.

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