Table 4. High-temperature enthalpy measurements on aluminum carbide (Al4C3).
| Furnace temperature |
Individual heat measurementsa | HT–H273.15 of Al4C3b | ||
|---|---|---|---|---|
| Sample + container | Container only | Mean observed | Obs.-calcd., eq (1)c | |
| °K | cal | cal | cal mol−1 | cal mol−1 |
| 373.2 | 285.0 | 149.6 | 2939d | −8 |
| 286.3 | 150.4 | |||
| 287.3 | 150.6 | |||
| 151.1 | ||||
| 473.2 | 600.4 | (306.8)e | 6305 | −27 |
| 602.4 | 310.1 | |||
| 601.8 | 309.8 | |||
| 311.1 | ||||
| 310.2 | ||||
| 573.2 | 936.9 | 475.2 | 9994 | +6 |
| 936.7 | 475.5 | |||
| 938.2 | ||||
| 936.8 | ||||
| 936.7 | ||||
| 936.7 | ||||
| 673.2 | 1289.7 | 648.0 | 13877 | +49 |
| 1288.9 | 647.9 | |||
| 1288.3 | ||||
| 773.2 | 1648.0 | 826.8 | 17794 | −8 |
| 1648.6 | 825.9 | |||
| 873.2 | 2021.1 | 1009.6 | 21883 | +4 |
| 2020.1 | 1009.9 | |||
| 973.2 | 2405.4 | 1205.9 | 25980 | −56 |
| 2406.0 | 1205.3 | |||
| 1073.2 | 2808.8 | 1409.1 | 30289 | +29 |
| 2807.7f | 1409.1 | |||
| 1173.2 | 3213.1f | 1615.6 | 34543 | +5 |
| 3210.4f | 1617.4 | |||
| 1614.5 | ||||
| 1616.9 | ||||
a
With all corrections applied, including those for the impurities in the sample. Sample mass=6.650 g.
b
Molecular weight of Al4C3=143.959.
c
The final values of (HT—H273.15) (table 5) are smaller than those calculated from eq (1) by 11.5 cal mol−1 at 373.15 °K and by 10 cal mol−1 at each of the other temperatures in table 4.
d
The value found from the measurements with the adiabatic calorimeter is 2933.0 cal mol−1.
e
Omitted from the mean because of inferior precision.
f
In these measurements 0.003 g of the sample had been removed, but these values have been corrected to a basis of the 6.650 g of sample present in the other measurements in this column.