Standard molar entropy

About: Standard molar entropy is a research topic. Over the lifetime, 1586 publications have been published within this topic receiving 29886 citations.

Determination of thermodynamic functions for nano-materials via the electrochemical method

Abstract: Take nano-copper for an example, the electrochemical method is firstly used to obtain the thermodynamic functions of nano-materials. The nano-copper electrode, particle size of about 80 nm, is prepared by electrochemical deposition. Determine the potential difference between nano-copper and bulk-copper, and take the known value of thermodynamic functions of bulk-copper as reference standard, depending on the thermodynamic relations of nano and bulk-copper, it can simply get the standard molar enthalpy of formation, standard molar Gibbs free energy and standard molar entropy, which is 5.16 kJ mol-1、0.216 kJ mol-1、49.75 J K-1 mol-1 respectively, meanwhile, the heating effect of reversible cell for nano-copper is -4.95 kJ mol-1.

Thermodynamics of lanthanum uranovanadate

Abstract: Temperature dependence of heat capacity in the range 80-300 K, as well as absolute entropy and standard formation enthalpy, entropy, and Gibbs function at 298.15 K were determined for La(VUO6)3&· 10H2O by reaction and adiabatic vacuum calorimetry. Thermodynamic characteristics of dehydration, synthesis, and solution of the compound were calculated.

Low-temperature heat capacity and standard molar enthalpy of formation of potassium L-threonate hydrate K(C4H7O5)center dot H2O

Abstract: The solid potassium L-threonate hydrate, K(C4H7O5)(H2O)-H-., was synthesized by the reaction of L-threonic acid with aqueous potassium hydrogen carbonate and characterized by means of chemical and elemental analyses, IR and TG-DTG. Low-temperature heat capacity of K(C4H7O5)(H2O)-H-. has been precisely measured with a small sample precise automated adiabatic calorimeter over the temperature range from 78 to 395 K. An obvious process of the dehydration occurred in the temperature region of 364-382 K. The peak temperature of the dehydration of the compound has been observed to be (380.524 +/- 0.093) K by means of the heat capacity measurements. The molar enthalpy, Delta(d)H(m), and molar entropy, Delta(d)S(m), of the dehydration of K(C4H7O5)(H2O)-H-. were calculated to be (19.655 +/- 0.012) kJ/mol and (51.618 +/- 0.051) J/(K-mol) by the analysis of the heat-capacity curve. The experimental molar heat capacities of the solid from 78 to 362 K and from 382 to 395 K have been respectively fitted to two polynomial equations of heat capacities against the reduced temperatures by least square method. The constant-volume energy of combustion of the compound, Delta(c)U(m), has been determined to be (-1749.71 +/- 0.91) kJ(.)mol(-1) by an RBC-II precision rotary-bomb combustion calorimeter at 298.15 K. The standard molar enthalpy of formation of the compound, Delta(f)H(m)(theta) has been calculated to be (- 1292.56 +/- 1.06) kJ(.)mol(-1) from the combination of the standard molar enthalpy of combustion of the compound with other auxiliary thermodynamic quantities.

Synthesis and thermodynamic properties of a new task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate

Abstract: Task-specific ionic liquid 1-butyl-3-methylimidazolium salicylate ([BMI]Sal) was synthesized in two steps. In the temperature range of 298.15–353.15 K, the density and surface tension for pure ionic liquid were determined and the thermodynamic properties of the ionic liquid were discussed in terms of Glasser’s theory. The standard molar entropy and lattice energy for [BMI]Sal have been estimated. In addition, the thermal expansion coefficient, α = 5.53 × 10−4 K−1, calculated by the interstice model is in extreme agreement with α (experimental) = 5.50 × 10−4 K−1.