Molar entropy change

The molar entropy change for the reversible process, calculated... 

Notation AH, means standard molar heat effect when monomer in state x is transformed into polymer is state y. AS, means standard molar entropy change, when monomer in state x is transformed into polymer in state y. 

Forster cycle Indirect method of determination of excited state equilibria, such as pK values, based on ground state thermodynamics and electronic transition energies. This cycle considers only the difference in molar enthalpy change (AAH) of reaction of ground and excited states, neglecting the difference in molar entropy change of reaction of those states (AAS). 

Let us consider the generation of long chains of a statistical binary copolymer at low conversions. The reaction of the active centre with the monomer exhibits the characteristic molar heat of reaction H and molar entropy change S... 

Ig k2 for the Menschutkin reaction of tri- -propylamine with iodomethane (Drougard and Decroocq) standard molar entropy change standard molar entropy of activation solvophobic power of a solvent (Abraham)... 

Although many water molecules are associated with ferroin cations on solvent extraction (280, 526), and the radii of FeLl" " ions in water, 11.8 A for L = bipy and 13.0 A for phen, show the presence of attached water molecules (466), the partial molar entropy changes for processes ML3+ -> ML + are small (278, 439). The data for several substituted Fe(III) complexes in acetonitrile show little change in the entropy change on reduction, although the changes are marked in water, implying a specific interaction between substituent and solvent water (439). 

If the normal boiling point of a liquid is 67 °C, and the standard molar entropy change for the boiling process is +100 J/K, estimate the standard molar enthalpy change for the boiling process. 

Poly(tetrafluoroethylene) melts at approximately 327°C. If the heat of fusion is AHfas = 5.28 kJ moE what is the molar entropy change of fusion (ASfJ) ... 

Diethyl ether is a hquid at normal temperature and pressure, and it bods at 3 5°C. Given that AH is 26.0 y/mol for the vaporization of diethyl ether, find its molar entropy change for vaporization. 

Retention in chromatography is controlled by thermodynamic equilibria. The partition ofthe analyte between the mobile and the stationary phase is in control of the retention factor. This partition can be described by the laws of reversible thermodynamics. Therefore, we also borrow the thermodynamic description of the temperature dependence of equilibria. This is the so-called van t Hoff equation, which is the quantitative expression of the Le Chatelier principle. According to this, the temperature dependence of the retention factor k can be described by 2.9, with R being the general gas constant, AH° the molar enthalpy (heat tone) related to the transition of the analyte from mobile to stationary phase, AS° the molar entropy change for this transition, andj( the so-called phase ratio of the packed stationary phase in the column. 

The molar enthalpy change A /fm and molar entropy change A m at the melting temperature. 

When pure ideal gases mix at constant T and p to form an ideal gas mixture, the molar entropy change A5 (mix) = -R yt In (Eq. 11.1.9) is positive. 

The molar heats of fusion and vaporization of ethanol are 7.61 and 26.0 kJ/mol, respectively. Calculate the molar entropy changes for the solid-liquid and liquid-vapor transitions for ethanol. At 1 atm pressure, ethanol melts at — 117.3°C and boils at 78.3 C. 

Similar information can also be obtained from the standard molar entropy change on ion pairing, A S [41], Table 7.5. This number is obtained from the entropy of desolvation, A S°, divided by the entropy of fusion of the solvent extrapolated to the temperature employed, The former of these two quantities is obtained according... 

Calculate the molar entropy change of the gas that accompanies the bursting of a balloon if the initial pressure is 2.55 atm and the external pressure is 0.97 atm. 

The molar entropy change for a process is 1.00 J/mol-K. By what percentage has the number of possible distributions n changed when going from reactants to products You will need to use the relationship in equation 3.26. 

What is the molar entropy change for this reaction ... 

Even for an open system one can easily express the entropy flux as written in Eq. (2). Calorimetry can give information on the heat flux, dQ/dt, which increases the entropy of the system as written in Eq. (2). Since the temperature is constant inside the system during the time interval, dt, the heat flux into the system can be considered reversible. Any irreversibility caused by temperature jumps (needed to cause the heat flux) is pushed, as mentioned above, into the boundary and is of no interest to the description of the system. The changes caused by the flux of matter can be measured, for example, by thermogravimetry. The matter flux, dgnj/dr, of substance i across the system boundary in the time interval, dr must be multiplied with the molar change in entropy due to the flux, 5j. The molar entropy change must be known or measured separately — for example by heat capacity measurements from zero kelvin to T, as outlined by Eq. (12) of Fig. 2.4. 

Combining Eq. (2.26) for the molar enthalpy change and Eq. (2.20) for the molar entropy change, we arrive at the Flory-Huggins equation for the Gibbs free energy ... 

On the left side of the equation is the molar volume change AVtr = K - Vp for the phase transition. Likewise, on the right side is the molar entropy change for the transition. 

In addition to phase stability analysis already discussed (see section 2.3.1) the data of Bevan and Kordis (1964) on the Ce02- -02 system and new isothermal data obtained by Panlener et al. (1975) has been analyzed for the composition range Ce02.o to CeOi.70 over a pressure range of 10 to 10 atm of oxygen for a series of isotherms from 750-1500°C. Blumenthal (1975) found that in the composition range 0.001 < S < 0.01 the partial molar entropy change was consis-... 

What is the standard molar entropy change for the vaporization of water at 373 K given that the standard molar enthalpy of vaporization is 40.7 kJ moP at this temperature ... 

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