标准状况

标准状况(英語:standard temperature and pressure, STP标准温度与标准压力),简称「标况」。由於地表各處的溫度壓力皆不同,即使是同一地點的溫度壓强也隨測量時間不同而相異,因此為研究方便,制定出描述物質特徵的標準狀況。

在化学领域,国际纯化学和应用化学联合会(IUPAC)在1982年改变了标准温度和标准压力(STP)的定义:

  • 在1982年以前,标准状况定义为0 (273.15 K)、101325 / 105 Pa(1 atm)。1摩尔的理想氣體在STP下占有的體積為22.414升(L)。
  • 自1982年以来,标准状况定义为0 ℃(273.15 K)、100kPa,這樣的定義接近海平面冰點。1摩尔的理想氣體在STP下占有的體積為22.710953(21)L(CODATA 2010),為標準摩尔體積(standard molar volume)。這是区别一般条件而制定的标准。

历史上由巴黎制定的通行欧洲的舊制標準如下:

  • 压强p = 1 atm = 101325 帕斯卡 = 1013.25 hPa = 101.325 kPa = 1.01325 bar.
  • 温度T = 298.15 K ≙ 25 °C,空气密度ρ = 1.184 kg/m³.
现在也使用T = 293.15 K ≙ 20 °C 空气密度ρ = 1.204 kg/m³.

化学生物化学中另外还包括定义的观察反应物浓度,一般情况下为1mol/L(1 M)。[來源請求]在生物化学中只有氢离子例外(H+)。限定pH为7,即10-7 mol/l H+离子浓度用于准生理条件描述,肌体条件,细胞内部条件等。

当前使用的标准状况编辑

世界各地的组织目前正在使用许多不同的标准状况定义。 下表列出了其中的一些。 其中一些组织过去使用过其他标准。 例如,自1982年以来,IUPAC将标准参考条件定义为0°C和100 kPa(1 bar),而其旧标准为0°C和101.325 kPa(1 atm)。

标准状况參考條件
溫度 絕對壓力 相对湿度 出版或創立者
°C kPa % RH
0 100.000   IUPAC(1982年之后正在使用的定義)
0 101.325   IUPAC(1982年以前使用的定義)NIST[1], ISO 10780[2]
15 101.325 0[3][4] ICAO's ISA[3] ISO 13443,[4] EEA[5] EGIA[6]
20 101.325   EPA[7] NIST[8]
25 101.325   EPA[9]
25 100.000   SATP[10]
20 100.000 0 CAGI[11]
15 100.000   SPE[12]
°F psi % RH
60 14.696   SPE,[12] U.S. OSHA[13] SCAQMD[14]
60 14.73   EGIA,[6] OPEC[15] U.S. EIA[16]
59 14.503 78 U.S. Army Standard Metro[17][18]
59 14.696 60 ISO 2314, ISO 3977-2[19]
°F in Hg % RH
70 29.92 0 AMCA[20][21] air density = 0.075 lbm/ft³. This AMCA standard applies only to air.

注釋:

  • EGIA:加拿大电力和燃气检验法
  • SATP:标准的环境压力和温度
  • SCAQMD:加州南海岸空气质量管理区

气体摩尔体积编辑

当表示气体的摩尔体积时,要指明适用的温度和压力条件。 在不指明温度和压力条件的情况下,说明气体的摩尔体积几乎没有意义并且可能引起混淆。

通过使用理想气体定律,可以计算在标准状况下的气体摩尔体积。 任何理想气体的摩尔体积可以在各种标准参考条件下计算,如下所示:

  • Vm = 8.3145 × 273.15 / 101.325 = 22.414 dm3/mol (在 0 °C 和 101.325 kPa 下)
  • Vm = 8.3145 × 273.15 / 100.000 = 22.711 dm3/mol (在 0 °C 和 100 kPa 下)
  • Vm = 8.3145 × 298.15 / 101.325 = 24.466 dm3/mol (在25 °C 和 101.325 kPa 下)
  • Vm = 8.3145 × 298.15 / 100.000 = 24.790 dm3/mol (在25 °C 和 100 kPa 下)
  • Vm = 10.7316 × 519.67 / 14.730 = 378.61 ft3/lbmol (在60 °F 和 14.73 psi 下)

参看编辑

參考資料编辑

  1. ^ NIST. NIST Standard Reference Database 7 – NIST Electron and Positron Stopping Powers of Materials Database. 1989 [08-07-25]. (原始内容存档于2011-06-29). If you want the program to treat the material as an ideal gas, the density will be assumed given by M/V, where M is the gram molecular weight of the gas and V is the mol volume of 22414 cm3 at standard conditions(0 deg C and 1 atm). 
  2. ^ ISO, ISO 10780:1994 : Stationary source emissions - Measurement of velocity and volume flowrate of gas streams in ducts, 1994 [2008-12-20], (原始内容存档于2016-03-03) 
  3. ^ 3.0 3.1 Robert C. Weast (Editor). Handbook of Physics and Chemistry 56th Edition. CRC Press. 1975: F201–F206. ISBN 0-87819-455-X. 
  4. ^ 4.0 4.1 "Natural gas – Standard reference conditions", ISO 13443, International Organization for Standardization, Geneva, Switzerland  ISO Standards Catalogue页面存档备份,存于互联网档案馆
  5. ^ "Extraction, First Treatment and Loading of Liquid & Gaseous Fossil Fuels", Emission Inventory Guidebook B521, Activities 050201 - 050303, September 1999, European Environmental Agency, Copenhagen, Denmark  Emission Inventory Guidebook[永久失效連結]
  6. ^ 6.0 6.1 "Electricity and Gas Inspection Act", SOR/86-131(defines a set of standard conditions for Imperial units and a different set for metric units) Canadian Laws页面存档备份,存于互联网档案馆
  7. ^ "Standards of Performance for New Sources", 40 CFR--Protection of the Environment, Chapter I, Part 60, Section 60.2, 1990  New Source Performance Standards页面存档备份,存于互联网档案馆
  8. ^ "Design and Uncertainty for a PVTt Gas Flow Standard", Journal of Research of the National Institute of Standards and Technology, Vol.108, Number 1, 2003  NIST Journal 互联网档案馆存檔,存档日期2006-04-14.
  9. ^ "National Primary and Secondary Ambient Air Quality Standards", 40 CFR--Protection of the Environment, Chapter I, Part 50, Section 50.3, 1998  National Ambient Air Standards页面存档备份,存于互联网档案馆
  10. ^ "Table of Chemical Thermodynamic Properties", National Bureau of Standards(NBS),Journal of Physics and Chemical Reference Data, 1982, Vol. 11, Supplement 2.
  11. ^ "Glossary", 2002, Compressed Air and Gas Institute, Cleveland, OH, USA  Glossary 互联网档案馆存檔,存档日期2007-10-28.
  12. ^ 12.0 12.1 The SI Metric System of Units and SPE Metric Standard 互联网档案馆存檔,存档日期2008-12-20. 1984, Richardson, TX, USA(Notes for Table 2.3 on page 25 define standard cubic foot and standard cubic meter)
  13. ^ "Storage and Handling of Liquefied Petroleum Gases" and "Storage and Handling of Anhydrous Ammonia", 29 CFR--Labor, Chapter XVII--Occupational Safety and Health Administration, Part 1910, Sect. 1910.110 and 1910.111, 1993  Storage/Handling of LPG 互联网档案馆存檔,存档日期2006-07-19.
  14. ^ "Rule 102, Definition of Terms(Standard Conditions)", Amended December 2004, South Coast Air Quality Management District, Los Angeles, California, USA  SCAQMD Rule 102 互联网档案馆存檔,存档日期2008-12-19.
  15. ^ "Annual Statistical Bulletin", 2004, Editor-in-chief: Dr. Omar Ibrahim, Organization of the Petroleum Exporting Countries, Vienna, Austria  OPEC Statistical Bulletin 互联网档案馆存檔,存档日期2008-12-19.
  16. ^ "Natural Gas Annual 2004", DOE/EIA-0131(04),December 2005, U.S. Department of Energy, Energy Information Administration, Washington, D.C., USA  Natural Gas Annual 2004页面存档备份,存于互联网档案馆
  17. ^ Sierra Bullets L.P. Chapter 3 – Effects of Altitude and Atmospheric Conditions. Rifle and Handgun Reloading Manual, 5th Edition. [2008-12-20]. (原始内容存档于2006-03-09). "Effects of Altitude and Atmospheric Conditions", Exterior Ballistics Section, Sierra's "Rifle and Handgun Reloading Manual, 5th Edition", Sedalia, MO, USA  Exterior Ballistics页面存档备份,存于互联网档案馆
  18. ^ The pressure is specified as 750 mmHg. However, the mmHg is temperature dependant, as mercury expands as temperature goes up. Here the values for the 0-20 °C range are given.
  19. ^ "Gas turbines – Procurement – Part 2: Standard reference conditions and ratings", ISO 3977-2:1997 and "Gas turbines - Acceptance tests", ISO 2314:1989, Edition 2, International Organization for Standardization, Geneva, Switzerland ISO页面存档备份,存于互联网档案馆
  20. ^ ANSI/AMCA Standard 210, "Laboratory Methods Of Testing Fans for Aerodynamic Performance Rating", as implied here: http://www.greenheck.com/pdf/centrifugal/Plug.pdf页面存档备份,存于互联网档案馆) when accessed on October 17, 2007
  21. ^ The standard is given as 29.92 inHg at an unspecified temperature. This most likely corresponds to a standard pressure of 101.325 kPa, converted into ~29.921 inHg at 32 °F)

外部連結编辑