Silver standard entropies

Consider the following example. Using information from the SQA Data Booklet and the fact that silver(l) nitrate and nitrogen dioxide have S° values of 142 and 241J K mol respectively, calculate the standard entropy change, AS°, for the decomposition of silver(l) nitrate ... 

The thermodynamic data AG , AH and S° of tellurium halides were calculated from the e.m.f. s of the galvanic cells and their temperature dependences (see IX.B) by taking into account the data for the other compounds which were involved in the total cell reactions Literature data of the standard enthalpies of formation and standard entropies of silver , silver iodide , silver chloride silver bromide and tellurium have been used in the calculations. 

Calculate the standard entropy of silver at 25 C (298 K) from the third lav/ of thermodynamics, assuming that the molar heat capacity at temperatures below -258°C HS K) follows Debye s equation. 

Thus, the standard entropy of silver at 250C is 10.25 cal/deg/mole. 

It may be noted that in this particular cell all the substances taking part in the reaction are in their respective standard states, thus simplifying the problem, [n this case dE /dT is equal to dE/dT, which is 3.38 X 10 volt deg. Since silver is univalent, the cell process would require the passage of J faraday, i.e., V is 1 equiv. Since the entropy is required in cal. deg. mole, it is convenient )o express F as 23,070 cal. volt g. equiv. (Table 1, Appendix), o that... 

Another procedure for testing the third law of thermodynamics is to combine heat content with entropy data for a given reaction, and so to determine the free energy change, the value of which is known from direct measurement. The standard free energy change for the formation of silver oxide, i.e., for the reaction 2Ag(s) + = Ag20(s), can be derived from... 

The solubility of silver chloride in pure water is 1.314 X 10 molal, and the mean ionic activity coefficient is then 0.9985 [Neuman, J. Am. Chem. Soc., 54, 2195 (1932)]. The heat of solution of the salt is 15,740 cal. mole". Taking the entropy of solid silver chloride as 22.97 e.u. mole ", and using the results of the preceding exercise, calculate the standard free energy and heat of formation and the entropy of the Cl" ion at 25 C. 

By a similar procedure, evaluate the standard molar entropy, the standard molar entropy of formation, and the standard molar Gibbs energy of formation of crystalline silver chloride at 298.15 K. You need the following standard molar entropies evaluated from spectroscopic and calorimetric data ... 

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