Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation Page: 97
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ENTROPIES OF INORGANIC SUBSTANCES AT 298.16 0K.
Sulfates.-Ishikawa and Murooka (218) obtained AH29,,.16 -56,322
and AF98.1= -59,209 for the reaction Zn(c) + Hg2SO4(c) = ZnSO4 (c)
2Hg(1), making AS298.16=9.68. This leads to SAs8.16=30.62 for
Barieau (35) has measured the heat capacities of ZnSO4.6H20(c)
(160-3050) and ZnSO4.7H20(c) (150-3080), and Pollitzer (392, 393)
(270-2080) has measured ZnSO4-7H20(c). From Barieau's work,
S2098.16=85.9 0.3 for ZnSO4.6H20(c) and S298.16= 92.9 0.3 for ZnSO4-7
Zinc-Antimony Compounds.-DeWitt and Seltz (127) reported
S2,,.,=-21.4 for ZnSb(c), S2s.16=63.6 for Zn3Sb2(c), and S29s.16=73.5
for Zn4Sb3(c). These values are based upon e. m. f. measurements.
The uncertainties are estimated here as 1.4, 1.8, and 2.1,
Element.-The heat capacity of Zr(c) was measured by Todd (486)
(530-2970). The data yield S5,.oo= 1.00 (extrapolation), S29s.16-
S1.00=8.28 (measured), and S98.16-=9.28 0.08.
Moore's (364) compilation of spectroscopic data for Zr(g) shows that
at 298.160 three energy levels must be considered in deriving the en-
tropy. The term values are 0, 570.41, and 1,240.84 cm.-', and the
quantum weights are 5, 7, and 9, respectively. These states add 3.873
to the Sackur equation to make S9,,.1,=43.32 0.01 for Zr(g).
Oxides.-Kelley (286) (540-2950) measured the heat capacity of
ZrO2(c). The data yield S0.12=0.44 (extrapolation), S298.16 -S50.12=
11.68 (measured), and S298.16=12.12 0.08.
The entropy of ZrO(g) may be calculated from data listed by Herz-
berg (212), which correspond to 1=45.3X10-40 and co=933. Three
electronic energy levels are to be considered. They have term values
of 0, 292.1, and 605.5 cm.-1 and the quantum weight is 2 in each
instance. There are computed St+r,298.16 53.479, S,298.16 0.122,
Se,298.16=- 2.280, and S298.16= 55.88 0.10.
Chloride.-The heat capacity of ZrC14(c) was measured by Todd
(486) (520-2970). His data yield S1.00--8.12 (extrapolation), S298.16-
S 1.oo--36.39 (measured), and S298.16=44.5 0.5.
From data given by Kelley (270), the entropy of sublimation of
ZrC14(c) is AS0g,.16=49.1. This and the value above result in S298.18
=93.6 2 for ZrC14 (g).
Nitride.-Todd (486) (530-2970) measured the heat capacity of
ZrN (c). His data give S1.oo=-0.41 (extrapolation), Sos.1-S1.oo= 8.88
(measured), and S .16-= 9.29 0.05.
Silicate.-The heat capacity of ZrSiO4(c) (zircon) was measured by
Kelley (282) (520-2590). The data yield S0.12=--0.56 (extrapolation).
S298.1-S50.12= 19.64 (measured), and S298.16= 20.2 0.2.
The application of the Sackur equation, with R In 2 added for elec-
tron sDin, to electron gas gives Ss9.16=4.99- 0.01.
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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/m1/101/: accessed May 19, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.