Trojna tačka
Trojnu tačku neke supstance određuju temperatura i pritisak na kojoj se ona nalazi u termodinamičkoj ravnoteži sva tri agregatna stanja (gas, tečnost, i čvrsto stanje).[1] Na primer, trojna tačka žive je na -38.8344 °C, i pri pritisku od 0.2 mPa.
Osim trojne tačke za čvrstu, tečnu i gasovitu fazu, trojna tačka može da obuhvata više od jedne čvrste faze, za supstance sa višestrukim polimorfima. Helijum-4 je specijalni slučaj koji ima trojnu tačku sa dve različite tečne faze (lambda tačka).[1]
Trojna tačka vode je pri pritisku od 611,657 ± 0,010 Pa i na 0,01 °C. Jedinica Međunarodnog sistema jedinica kelvin se definiše preko trojne tačke vode. Trojna tačka vode se realizuje u specijalnim staklenim sudovima spoljašnjeg prečnika od 4 do 7 cm koji imaju aksijalno postavljenu šupljinu otvorenu odozgo za smeštaj termometra.
Termin „trojna tačka“ je skovao 1873. godine James Thomson,[2] brat Lorda Kelvina.[3][4][5][6]
Tabela trostrukih tački
Ova tabela sadrži trojne tačke prelaza gasa, tečnosti i čvrstog stanja za nekoliko supstanci. Ukoliko nije drugačije napomenuto, podaci su preuzeti od SAD Nacionalnog biroa za standarde (sad NIST, engl. National Institute of Standards and Technology).[7]
| Supstanca | T [K] (°C) | p [kPa]* (atm) |
|---|---|---|
| Acetilen | 0192.4 192.4 K (−80.7 °C) | 7002120000000000000♠ 120 kPa (1.2 atm) |
| Amonijak | 0195.40 195.40 K (−77.75 °C) | 7003607600000000000♠ 6.076 kPa (0.05997 atm) |
| Argon | 0083.81 83.81 K (−189.34 °C) | 7002689000000000000♠ 68.9 kPa (0.680 atm) |
| Arsenik | 1090 1,090 K (820 °C) | 7003362800000000000♠ 3,628 kPa (35.81 atm) |
| Butan[8] | 0134.6 134.6 K (−138.6 °C) | 6996700000000000000♠ 7× 10−4 kPa |
| Ugljenik (grafit) | 4765 4,765 K (4,492 °C) | 7004101320000000000♠ 10,132 kPa (100.00 atm) |
| Ugljen dioksid | 0216.55 216.55 K (−56.60 °C) | 7002517000000000000♠ 517 kPa (5.10 atm) |
| Ugljen monoksid | 0068.10 68.10 K (−205.05 °C) | 7003153700000000000♠ 15.37 kPa (0.1517 atm) |
| Hloroform[9] | 0175.43 175.43 K (−97.72 °C) | 7002870000000000000♠ 0.870 kPa (0.00859 atm) |
| Deuterijum | 0018.63 18.63 K (−254.52 °C) | 7002171000000000000♠ 17.1 kPa (0.169 atm) |
| Etan | 0089.89 89.89 K (−183.26 °C) | 6996800000000000000♠ 8 × 10−4 kPa |
| Etanol[10] | 0150 150 K (−123 °C) | 6994429999999999999♠ 4.3 × 10−7 kPa |
| Etilen | 0104.0 104.0 K (−169.2 °C) | 7001120000000000000♠ 0.12 kPa (0.0012 atm) |
| Mravlja kiselina[11] | 0281.40 281.40 K (8.25 °C) | 7001220000000000000♠ 2.2 kPa (0.022 atm) |
| Helijum-4 (lambda tačka) | 0002.19 2.19 K (−270.96 °C) | 7001510000000000000♠ 5.1 kPa (0.050 atm) |
| Heksafluoroetan[12] | 0173.08 173.08 K (−100.07 °C) | 7003266000000000000♠ 26.60 kPa (0.2625 atm) |
| Vodonik | 0013.84 13.84 K (−259.31 °C) | 7002704000000000000♠ 7.04 kPa (0.0695 atm) |
| Vodonik hlorid | 0158.96 158.96 K (−114.19 °C) | 7002139000000000000♠ 13.9 kPa (0.137 atm) |
| Jod[13] | 0386.65 386.65 K (113.50 °C) | 7003120700000000000♠ 12.07 kPa (0.1191 atm) |
| Izobutan[14] | 0113.55 113.55 K (−159.60 °C) | 6999194810000000000♠ 1.9481 × 10−5 kPa |
| Živa | 0234.2 234.2 K (−39.0 °C) | 6995164999999999999♠ 1.65 × 10−7 kPa |
| Metan | 0090.68 90.68 K (−182.47 °C) | 7002117000000000000♠ 11.7 kPa (0.115 atm) |
| Neon | 0024.57 24.57 K (−248.58 °C) | 7002432000000000000♠ 43.2 kPa (0.426 atm) |
| Azot-monoksid | 0109.50 109.50 K (−163.65 °C) | 7003219200000000000♠ 21.92 kPa (0.2163 atm) |
| Azot | 0063.18 63.18 K (−209.97 °C) | 7002126000000000000♠ 12.6 kPa (0.124 atm) |
| Azotasta kiselina | 0182.34 182.34 K (−90.81 °C) | 7003878500000000000♠ 87.85 kPa (0.8670 atm) |
| Kiseonik | 0054.36 54.36 K (−218.79 °C) | 7002152000000000000♠ 0.152 kPa (0.00150 atm) |
| Paladijum | 1825 1,825 K (1,552 °C) | 6998350000000000000♠ 3.5 × 10−3 kPa |
| Platina | 2045 2,045 K (1,772 °C) | 6996200000000000000♠ 2.0 × 10−4 kPa |
| Sumpor dioksid | 0197.69 197.69 K (−75.46 °C) | 7002167000000000000♠ 1.67 kPa (0.0165 atm) |
| Titanijum | 1941 1,941 K (1,668 °C) | 6998530000000000000♠ 5.3 × 10−3 kPa |
| Uranijum heksafluorid | 0337.17 337.17 K (64.02 °C) | 7003151700000000000♠ 151.7 kPa (1.497 atm) |
| Voda | 0273.16 273.16 K (0.01 °C) | 7003611700000000000♠ 0.6117 kPa (0.006037 atm) |
| Ksenon | 0161.3 161.3 K (−111.8 °C) | 7002815000000000000♠ 81.5 kPa (0.804 atm) |
| Cink | 0692.65 692.65 K (419.50 °C) | 7001650000000000000♠ 0.065 kPa (0.00064 atm) |
* Napomena: radi poređenja, tipični atmosferski pritisak je 101,325 kPa (1 atm).
Reference
- ↑ 1,0 1,1 Međunarodna unija za čistu i primenjenu hemiju (1994). "Triple point". Kompendijum Hemijske Terminologije Internet edition.
- ↑ Thomson, James; Larmor, Joseph (1912). Collected Papers in Physics and Engineering. University Press. str. civ. , at Google books
- ↑ James Thomson (1873) "A quantitative investigation of certain relations between the gaseous, the liquid, and the solid states of water-substance," Proceedings of the Royal Society, 22 : 27-36. From a footnote on page 28: " … the three curves would meet or cross each other in one point, which I have called the triple point."
- ↑ Buchwald, J.Z. (1977). „William Thomson and the mathematization of Faraday's electrostatics”. Historical Studies in the Physical Sciences 8: 101–136. DOI:10.2307/27757369.
- ↑ Burchfield, J.D. (1990). Lord Kelvin and the Age of the Earth. University of Chicago Press. ISBN 0-226-08043-9.
- ↑ Cardoso Dias, D.M. (1996). „William Thomson and the Heritage of Caloric”. Annals of Science 53 (5): 511–520. DOI:10.1080/00033799600200361.
- ↑ Cengel, Yunus A.; Turner, Robert H. (2004). Fundamentals of thermal-fluid sciences. Boston: McGraw-Hill. str. 78. ISBN 0-07-297675-6.
- ↑ See Butane
- ↑ See Chloroform
- ↑ See Ethanol
- ↑ See Formic acid
- ↑ See Hexafluoroethane
- ↑ Walas, S. M. (1990). Chemical Process Equipment – Selection and Design. Amsterdam: Elsevier. str. 639. ISBN 0-7506-7510-1.
- ↑ See Isobutane
Spoljašnje veze
- Definicija kelvinovog stepena
- Definicija kelvinovog stepena
- Voda na trojnoj tački (video)
- Fazni dijagram vode
- Verzeichnis von Datenbanken und Nachschlagewerken mit Tripelpunkten Arhivirano 2016-03-04 na Wayback Machine-u
