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J. W. Hill, R. H. Petrucci, T. W. McCreary, & S. S. Perry General Chemistry 4th edition

Problem 17.85

Use thermodynamic data from Appendix C to obtain a value of Ksp for Ag2SO4, and compare your result with the one found in the table of solubility product constants in Appendix C.






Answer:

The reaction is:

Ag2SO4(s)2 Ag+(aq) + SO42–(aq)

Gof(SO42–) = –744.5 kJ/mol
Gof(Ag+) = 77.11 kJ/mol
Gof(Ag2SO4) = –618.5 kJ/mol

Go = [2(77.11) + –744.5] – [–618.5] = 28.2 kJ

Go = –RTln Keq = –RTlnKsp

28200 = –(8.314)(298)ln Ksp
ln Ksp = –11.4
Ksp = e–11.4 = 1×10–5

From the Table, Ksp = 1.4×10–5; the two values are the same, within error.