hi,
hat jemand von euch die Stoffwerte von Eis in einem Temperaturbereich von 0 bis -25°C.
Oder weiss jemand wo ich sie im net finden kann.
gruss thomas
hat jemand von euch die Stoffwerte von
Eis in einem Temperaturbereich von 0 bis
-25°C.
Was hättest Du denn gerne???
Dichte, Thermodynamische Daten, Härte, Wärmeleitfähigkeit…???
Gandalf
Was hättest Du denn gerne???
Dichte, Thermodynamische Daten, Härte,
Wärmeleitfähigkeit…???
so ziemlich alles was zuu finden ist.
gruss thomas
so ziemlich alles was zu finden ist.
gruss thomas
Dann empfehle ich das „Gmelin Handbuch der Anorganischen Chemie“ und „Landold Börnstein Zahlenwerte und Funktionen aus Physik Chemie…“ Gibt es in allen Unibibliotheken, die Chemie anbieten.
Gandalf
so ziemlich alles was zuu finden ist.
gruss thomas
Unten hab ich noch was aus dem Ullmann kopiert. Die Tabellen und Abbildungen können leider nicht rübergebracht werden.
Gandalf
2.1. Properties of Ice
2.1.1. Thermodynamic Properties
Today, a total of 12 modifications of ice are known [29][30][31]. The phase diagram of ice in the p – T projection in the temperature range –100 to +600 °C and pressures up to >104 MPa is shown in Figure (8) [32], [33]. The densities at 500 °C have also been entered for comparison. Natural ice exists as ice Ih and crystallizes hexagonally. In general, only this modification is of interest for technical processes. A metastable cubic variant of this modification also exists. In Figure (8), ice IV (a metastable modification, which occurs in the phase region of ice V) and ice VIII (with a triple point at ca. 5 °C and 2100 MPa, which is formed from ice VI or ice VII at higher pressure and lower temperature) are not shown. Ice IX and ice XII have also been excluded from Figure (8) because they lie outside the temperature and pressure region depicted in this figure. All known triple points are listed in Table (5) [31], [34].
Table (5) shows that modification II, for example, is not formed directly from liquid water on cooling or compression but can originate only from modifications Ih, III, V, or VI. An anomaly of water is that the melting pressure curve for ice Ih exhibits a negative slope up to the triple point Ih – III – liquid at 207 MPa and –22 °C. The values of the melting pressure curve ice Ih – liquid water are summarized below in tabular form down to this triple point [35].
t, °C
p, MPa
0.0098
6.1156×10–4
0.0
0.10132
–5.0
59.8
–10.0
110.8
–15.0
155.9
–20.0
193.2
–22.0
207.4
The following equation describes the melting pressure curve of ice Ih in equilibrium with water [36] :
The sublimation pressure curve of ice Ih – water vapor is known down to –110 °C :
t, °C
p×103, hPa
0
6108
–10
2597
–20
1032
–30
380.1
–50
39.37
–70
2.59
–90
0.093
–110
0.0013
The heat of fusion of ice Ih – water is 333.69 kJ/kg at 0 °C, and the heat of sublimation of ice Ih – water vapor is 2838 kJ/kg at 0 °C [37], [38].
The molar heat capacity Cp of ice was investigated for ice Ih. Down to –140 °C, the following equation is valid [39] :
The parameters of this equation were determined by fitting the data of GIAUQUE and STOUT [35].
T, K
Cp , J mol–1 K–1
10
0.276
20
2.050
50
7.931
100
15.879
150
22.025
200
28.211
250
34.829
270
37.481
2.1.2. Transport Properties
For the thermal conductivity l of ice, the following equation is valid in the temperature range 0 to –170 °C [37], [38] :
The self-diffusion coefficient D is
[34].
2.1.3. Electrolytic Properties
Relative Permittivity. The relative permittivity e was determined on polycrystalline ice at a frequency of n = 0 Hz :
t, °C
–0.1
–20.9
–44.7
–65.8
e
91.5
97.4
104
133
The relative permittivity increases with decreasing temperature. The phase change from one ice modification to the next-denser one is always accompanied by a jump in e to considerably higher values along the phase equilibriumcurves with liquid water [32]. Within one modification region, the relative permittivity increases only slightly with pressure. The more densely the water molecules are packed, the higher is the value of e.
The relative permittivity e depends on the frequency n of an applied electrical field. This frequency dependence provides information on the rotation of dipole molecules in the lattice. The dielectric relaxation time is a measure of how fast the polarization caused by an electrical field decays after the field is turned off. Reorientation times of the water molecules can also be determined by NMR studies [34].
The electrical conductivity k of ice was determined, e.g., at –10 °C [34], [40] :
2.1.4. Mechanical Properties
The mechanical properties of ice provide information on its stability and load capacity. The mechanical properties of ice Ih are listed below [37], [38] :
Mohs scratch hardness
at freezing point
£2
at –78.5 °C
»6
Tensile strength (–10 °C)
1 – 2 MPa
Compressive strength (–10 °C)
3 – 6 MPa
Young’s modulus (–16 °C)
9.42 GPa
Shear strength (–16 °C)
3.55 GPa
Poisson ratio (–16 °C)
0.33
(average)
[29] C. W. F. T. Pistorius, E. Rapoport, J. B. Clark, J. Chem. Phys. 48 (1968) 5509 – 5514.
hi gandalf,
vielen dank.
gruss thomas h.