NIST Standard Reference Database 30
Last Update to Data Content: 2002
"Enthalpy and Specific Heat of BaO in the High-Temperature Region 1200 - 2200°K," K. Irgashov, V.D. Tarasov, and V.Y. Chekhovskoi, High Temperature, Vol. 21 [5], pp. 688-691 (1983), published by Plenum Publishing Corporation.Language: English
"Barium oxide powder of very pure grade... was used as a starting material. The powder was melted in air using radiative heating by two "Uran" units simultaneously. After remelting the BaO granules were placed in hermetic weighing bottles from which they were removed to fill molybdenum ampuls; the ampuls were suspended, mounted in the experimental apparatus and demounted after the enthalpy measurement. ... the impurity content... can be estimated as... 0.2% - 0.3%."
The authors cite V.Y. Chekhovskoi et al., Teplofiz. Vys. Temp., Vol. 12, No. 6, 1239 (1974), and summarize the procedure as follows. "The enthalpy and specific heat of BaO were measured by the method of mixing in an apparatus consisting of a high-temperature furnace with a tungsten resistance heater and calorimeter. A water-cooled shutter was situated between furnace and calorimeter. The calorimeter consisted of a copper block surrounded by an isothermal shield. ...the temperature of the calorimeter was measured... by means of a quartz thermometer with an accuracy of 0.0001 K, while the temperature of the isothermal shield was held constant to 0.001 K by means of an automatic system based on an RTP-3M programmed controller. Barium oxide samples weighing 29 g to 38 g were placed in molybdenum ampuls... made from foil 0.1 mm thick and turned out of a rod. The weight of the first ampul was 4.5 g - 4.9 g, that of the second 23 g - 30 g. ... The geometrical dimensions of the ampuls were diameter 18 mm, height 40 mm. A cylinrical cavity was made along the axis of the ampuls with a height: diameter ratio of 10. This was used as a model blackbody to measure the temperature of the sample."
| Temperature ( K ) | Molar Heat Capacity ( J mol-1 K-1 ) | Specific Heat ( J kg-1 K-1 ) |
|---|---|---|
| 298.15 | 46.906 | 305.9 |
| 300 | 46.955 | 306.2 |
| 400 | 48.921 | 319.0 |
| 500 | 50.101 | 326.7 |
| 600 | 50.888 | 331.9 |
| 700 | 51.450 | 335.5 |
| 800 | 51.871 | 338.3 |
| 900 | 52.199 | 340.4 |
| 1000 | 52.462 | 342.1 |
| 1100 | 52.684 | 343.6 |
| 1300 | 53.172 | 346.8 |
| 1400 | 53.649 | 349.9 |
| 1500 | 54.603 | 356.1 |
| 1600 | 56.484 | 368.4 |
| 1700 | 59.968 | 391.1 |
| 1800 | 65.972 | 430.2 |
| 1900 | 75.652 | 493.4 |
| 2000 | 90.372 | 589.4 |
| 2100 | 111.649 | 728.1 |
| 2200 | 141.090 | 920.1 |