THE HEAT CAPACITY OF AQUEOUS SOLUTIONS OF HYDROFLUORIC ACID

1946 ◽  
Vol 24b (2) ◽  
pp. 51-56 ◽  
Author(s):  
T. Thorvaldson ◽  
E. C. Bailey
Keyword(s):  
Heat Capacity ◽  
Aqueous Solutions ◽  
Specific Heat ◽  
Hydrofluoric Acid ◽  
Temperature Range ◽  
Apparent Molal Heat Capacity

The heat capacity of aqueous solutions of hydrofluoric acid varying in concentration from 0.55 to 48% was determined over the temperature range 18° to 20 °C. The respective values for the specific heat varied between 0.996 and 0.718 cal. per gm. The values obtained are consistent among themselves but differ markedly from those found in the literature. The apparent molal heat capacity of the solute over this range of concentration and temperature was calculated and compared with values obtained from the data of other experimenters.

Protonation of azobenzene derivatives. I. Methyl orange and ortho-methyl orange

1973 ◽  
Vol 26 (5) ◽  
pp. 1005 ◽  
Author(s):  
PD Bolton ◽  
J Ellis ◽  
KA Fleming ◽  
IR Lantzke
Keyword(s):  
Heat Capacity ◽  
Methyl Orange ◽  
Aqueous Solutions ◽  
Standard Enthalpy ◽  
Acidity Constants ◽  
Temperature Range ◽  
Heat Capacity Changes ◽  
Azobenzene Derivatives

Thermodynamic acidity constants have been measured over the temperature range 5-50� for aqueous solutions of sodium 4?-dimethylaminoazobenzene- 4-sulphonate (methyl orange) and sodium 4?-dimethylaminoazobenzene-2- sulphonate (ortho-methyl orange). From these data values of the standard enthalpy, entropy, and heat capacity changes have been calculated for these compounds. These results are discussed in conjunction with previous spectrophotometric and other data with reference to the nature of the equilibrium systems involved in these protonation reactions. It is concluded that existing evidence does not allow an unequivocal assignment of the sites of protonation of these and related molecules.

CO2 capture using aqueous solutions of K2CO3+2-methylpiperazine and monoethanolamine: Specific heat capacity and heat of absorption

2016 ◽  
Vol 33 (12) ◽  
pp. 3465-3472 ◽  
Author(s):  
Young Eun Kim ◽  
Jeong Ho Choi ◽  
Soung Hee Yun ◽  
Sung Chan Nam ◽  
Yeo Il Yoon
Keyword(s):  
Heat Capacity ◽  
Aqueous Solutions ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Co2 Capture

Specific Heat Capacity Estimations for Biologically and Medicinally Important Compounds: Lidocaine Hydrochloride, Clove Oil and Piperine using DSC Technique

2020 ◽  
Vol 10 ◽  
Author(s):  
Gaurav Gupta ◽  
Vasim Shaikh ◽  
Sachin Kalas ◽  
Kesharsingh Patil
Keyword(s):  
Heat Capacity ◽  
Ionic Liquid ◽  
Heat Flow ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Chemical Potential ◽  
Lidocaine Hydrochloride ◽  
Clove Oil ◽  
Temperature Range ◽  
Thermal Gravimetry

Aims: To study the specific heat capacity for biologically and medicinally important compounds, namely, lidocaine hydrochloride, clove oil and brta-Piperine using DSC technique. Background: One of the main problems in the science of medicine is the application of drug molecules with limited solubility in water and in biofluids. Solubility is related to chemical potential of the solutes involved which imparts free energy avenues, a necessary requirement for equilibrium processes. The convincing solutions for solving this issue are the utilization of ionic liquids as drug. Lidocaine is the most widely utilized intraoral injected dental anesthetic prior to performing painful medical procedures. Besides that, lidocaine hydrochloride is a salt which is having melting point 76 0C (349 K) and behaves as ionic liquid after melting. Clove oil and β-piperine are very well-known naturally occurring medicinal compounds having broad spectrum of applications. Objective: To study the thermal gravimetry analysis behaviour for lidocaine hydrochloride, clove oil and β-piperine. To compute specific heat capacity at constant pressure, as a function of temperature for the studied systems. Method: In the present communication, the studies of thermal gravimetry analysis (TGA) and differential scanning calorimetry (DSC) for these compounds are described. The data of heat flow have been utilized to obtain specific heat capacity (Cp) values for lidocaine hydrochloride, clove oil and β-piperine over a temperature range in between 75 0C (348 K) and 155 0C (428 K) based upon the methodology we have developed. Result: The data of heat flow have been utilized to obtain specific heat capacity (Cp) values for lidocaine hydrochloride, clove oil and β-piperine over a temperature range in between 75 0C (348 K) and 155 0C (428 K) based upon the methodology we have developed. Conclusion: LC•HCl behaves as an ionic liquid between 76 and 230 0C (349 and 503 K). Clove oil is having lower specific heat capacity values and is similar to other organic aromatic compounds while piperine exhibits comparative high specific heat capacity values indicating possibilities of intramolecular hydrogen bonding which is generally not affected by temperature.

Estimation of the heat capacity of CdTe semiconductor

2016 ◽  
Vol 30 (04) ◽  
pp. 1650026 ◽  
Author(s):  
Hüseyin Koç ◽  
Erhan Eser
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Binomial Coefficient ◽  
Debye Model ◽  
The Other ◽  
Temperature Range ◽  
Theoretical Results ◽  
Good Agreement

The aim of this paper is to provide a simple and reliable analytical expression for the thermodynamic properties calculated in terms of the Debye model using the binomial coefficient, and examine specific heat capacity of CdTe in the 300–1400 K temperature range. The obtained results have been compared with the corresponding experimental and theoretical results. The calculated results are in good agreement with the other results over the entire temperature range.

Thermodynamic Properties of Ionized Gases at High Temperatures

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Kian Eisazadeh-Far ◽  
Hameed Metghalchi ◽  
James C. Keck
Keyword(s):  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
High Temperatures ◽  
Mole Fraction ◽  
Specific Heat Capacity ◽  
Local Equilibrium ◽  
Equilibrium Conditions ◽  
New Model ◽  
Temperature Range

Thermodynamic properties of ionized gases at high temperatures have been calculated by a new model based on local equilibrium conditions. Calculations have been done for nitrogen, oxygen, air, argon, and helium. The temperature range is 300–100,000 K. Thermodynamic properties include specific heat capacity, density, mole fraction of particles, and enthalpy. The model has been developed using statistical thermodynamics methods. Results have been compared with other researchers and the agreement is good.

scholarly journals HEAT CAPACITY PROPERTIES OF AQUEOUS BUFFER SOLUTIONS OF L-HISTIDINE IN A WIDE TEMPERATURE RANGE

2019 ◽  
Vol 62 (11) ◽  
pp. 78-84
Author(s):  
Elena Yu. Tyunina ◽  
Anna A. Kuritsyna
Keyword(s):  
Heat Capacity ◽  
Amino Acid ◽  
Specific Heat ◽  
Sodium Phosphate ◽  
Heat Capacities ◽  
Buffer Solution ◽  
Partial Molar Heat Capacities ◽  
Aqueous Buffer ◽  
Temperature Range ◽  
Buffer Solutions

The influence of temperature and concentration of L-histidine on the heat capacity properties of its aqueous buffer solutions was studied by differential scanning calorimetry. The investigations were carried out in aqueous buffer solutions (pH 7.4) containing monobasic sodium phosphate and dibasic sodium phosphate, which brings the environment closer to the conditions of real biological systems. The pH values of the solutions were fixed with a digital pH meter Mettler Toledo, model Five-Easy (Switzerland). The differential scanning microcalorimeter SCAL-1 (Biopribor, Pushchino, Russia) was used for measure the specific heat capacity of the system under study. It was equipped with Peltier thermoelectric elements, two measuring glass cells with an internal volume of 0.377 cm3, as well as a computer terminal and software for calculating heat capacity. The standard error of measurement of the specific heat for the studied solutions was within ±7·10-3 J·K-1·g-1. The experimental values of the specific heat of solutions of the amino acid in a phosphate buffer solvent in the temperature range (283.15 – 343.15) K were obtained. The concentration of histidine was varied from (0.00215 to 0.03648) mol·kg-1. All the studied solutions were prepared by the gravimetric method using Sartorius-ME215S scales (with a weighing accuracy of 1·10-5 g). The apparent molar heat capacities of L-histidine in the buffer solution, as well as its partial molar heat capacities at infinite dilution, were determined. The calculated molar parameters increase with an increase in both temperature and amino acid concentration. It was shown that the partial molar heat capacities transfers of L-histidine from water to the buffer solution have positive values in the temperature range studied. The results are discussed on base of the Gurney model.

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