Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation Page: 87
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ENTROPIES OF INORGANIC SUBSTANCES AT 298.16 8K.
2.11 (extrapolation), S298.16-S56.2=21.10 (measured), and S~8s.6=
Sulfate.-The thermodynamic properties of SrSO4(c) were consid-
ered by Kelley (273), S298.16=28.2 being estimated. No attempt will
be made to estimate the uncertainty in this value, which, however,
appears reasonable in comparison with the entropies of CaSO4(c)
Element.-The heat capacity of rhombic sulfur, S(rh), was measured
by Eastman and McGavock (137) (120-3660) and Nernst (373) (220-
202'). The more recent and more extensive data of the former in-
vestigators are adopted. There are obtained S5 .00o 0.12 (extrapola-
tion), S9,9s.13-S5.oo= 7.50 (measured), and S9S.18= 7.62 0.04.
Eastman and McGavock (137) (640-3780) and Nernst (373) (830-
2010) also measured the heat capacity of monoclinic sulfur, S(mon).
Again the values from Eastman and McGavock's work are adopted.
They compute 0.16 as the difference in entropy between the mono-
clinic and rhombic modifications, making Sos9.16= 7.78 0.06.
In calculating the entropy of S(g) at 298.160, three energy levels
must be considered. The compilation of Moore (364) gives the term
values as 0, 398, and 573 cm.- and the quantum weights as 5, 3, and
1, respectively. These states add 3.757 to the translational entropy
given by the Sackur equation, to make S9s.1=40.09 0.01.
Badger (32) has reinterpreted the spectroscopic data for S2(g) and
has obtained 1.840X 10-s cm. as the S-S distance. This corresponds
to 1=90.1X 10-40. According to Herzberg (212), the vibration fre-
quency is 723. The quantum weight of the ground state is 3. These
values yield S+r,298.16=51.936, SV,298.16=0.279, and Se,298.16=2.183.
The sum is S9"8.16=54.400.10 for S2(g). Cross (118) computed a
virtually identical value, while a different but incorrect figure, 53.85,
was reported by Godnev and Sverdlin (194). The result of Mont-
gomery and Kassel (363) is based upon the older interpretation of
the spectra which gave 1.60 X 10- cm. as the S-S distance.
From a recalculation (273) of the equilibrium data of Preuner and
Schupp (394), values were obtained leading to S,98.16-92 for S6(g) and
S298.16--109 for S8(g). The uncertainties in these values undoubtedly
are large but difficult to estimate.
Monoxide.-Herzberg (212) listed molecular-constant data for
SO(g) which correspond to I-39.5X10-40 and o 1,118. The quan-
tum weight of the ground state is 3. There are computed S+r,298s.8-=
50.815, SV,298.16=0.057, and Se,298.18= 2.183. The sum is S29S.16= 53.06
Dioxide.-Giauque and Stephenson (186) (150-2640) measured the
heat capacity of SO2. Their entropy calculation has been checked to
within 0.01 unit. The individual items are S5.00oo0.30 (extrapolation),
S197.4-S105.00=20.12 (crystals), AS197.64 1,769.1/197.64-8.95 (fusion),
263 .08-S197.64= 5.96 (liquid), AS263.08=5,960/263.08=- 22.65 (vaporiza-
tion at 1 atm. pressure), AS263.08= 0.09 (correction to ideal gas state),
and S298.16-S63.08= 1.17 (gas). The sum is S298.1-=59.24 0.10. This
value is adopted.
Molecular dimensions listed by Brockway (55) lead to I= 12.4 X
10-40, 12=87.0X 10-40, and 13=99.4 X 10-40 as the moments of inertia
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Kelley, K. K. Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation, report, 1950; Washington D.C.. (https://digital.library.unt.edu/ark:/67531/metadc12637/m1/91/: accessed April 19, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.