Contributions to the Data on Theoretical Metallurgy: [Part] 11. Entropies of Inorganic Substances: Revision (1948) of Data and Methods of Calculation Page: 47

ENTROPIES OF INORGANIC SUBSTANCES AT 298.160K.

47

to be added to the Sackur equation is 1.342, making S2s8.18=40.11
0.01 for Ge(g).
Oxide.-Molecular-constant data (212) for the GeO(g) molecule,
w=981 and 1=59.3 X 10-0, yield S+, 298.18= 53.45, S, 298.16= 0.10, and
S 98.1= 53.55 0.10.
Monogermane.-Clusius and Faber(94), Schifer and Barredo (411),
and Straley, Tindal, and Nielsen (475) have listed molecular-constant
data for GeH4(g). The values adopted for the present entropy cal-
culation are I1=12=3=9.7X10-40, 1=819(2), w22=931(3), w3-
2,090(1), and w4=2,114(3). There are computed St+r, 298.16=50.86,
S.298.16= 0.75, and S98.18= 50.60.3.
Clusius and Faber (94) (120-1660) have measured the heat capacity
and heats of transition, fusion, and vaporization of GeH4. Their data
are rather crude and do not permit an accurate entropy calculation.
However, an approximate check of the value from molecular-constant
data is possible. There are obtained S0.0=0.36 (extrapolation),
S73.2-S0.0= 11.49 (crystals III), AS3.2= 50/73.2= 0.68 (transition),
S7.5-S73.2= 0.61 (crystals II), AS8.5= 85/76.5=1.11 (transition),
S1007.3-S6.5=4.02 (crystals I), AS 07.3= 199.5/107.3=1.86 (fusion),
S894.8-S9 07.3= 7.96 (liquid), AS84.= 3,361/184.8= 18.19 (vaporization
at 1 atm. pressure), and ASs4.s= 0.15 (correction to ideal gas state).
These values add to give S'84.8=46.43 for GeH4(g) at the normal boil-
ing point, which is in fair agreement with the result calculated by
Clusius and Faber, 46.56, although details of the' two calculations
differ appreciably. Heating the gas from 184.80 to 298.160 involves
an entropy increase of 4.48. Therefore, S298.1=50.9 0.5. This
agrees within the limits of error with the molecular-constant result,
but it is worthy of no weight in comparison.
GOLD
Element.-Clusius and Harteck (100) (140-2130) measured the heat
capacity of Au(c). The extrapolated portion of the entropy below
14.10 is 0.11 and the measured portion is 11.28, making Sz98.16=11.39 :
0.10.
The entropy of Au(g) may be obtained from the Sackur equation
with R In 2 added to account for the quantum weight of the lowest
energy state. The result is Ss98.18=43.130.01.
Hydrides.-Molecular-constant data are available for AuH(g) and
AuD(g) (212). For the former, I=3.87X 10-40, and w=2,262, while
for the latter, I=7.69X 10-40, and = 1,613. These data yield
S98.,6 50.42:0.10 for AuH(g) and S98.16=51.810.10 for AuD
(g). The vibrational contribution to the entropy is less than 0.01 in
each instance.
HAFNIUM
Element.-The heat capacity of Hf(c) was measured by Cristescu
and Simon (117) (130-2100). The results of the entropy calculations
are S12.59= 0.013 (extrapolation), S98.1-S, 2.59= 13.06, and S98.16=
13.1 t0.2.
Available spectroscopic data (364) for Hf(g) show that its entropy
may be obtained by adding R In 5 to the Sackur equation. The
result is S98o.1=44.6510.01.

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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/m1/51/ocr/: accessed May 21, 2019), University of North Texas Libraries, Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.

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