고압하에서의 전지의 기전력과 열역학적 성질

The Electromotive Force and Thermodynamic Properties of the Cell at High Pressure

  • 지종기 (경북대학교 문리과대학 화학과) ;
  • 정종재 (경북대학교 문리과대학 화학과) ;
  • 황정의 (경북대학교 문리과대학 화학과)
  • Jee Jong-Gi (Department of Chemistry, College of Liberal Arts and Science, Kyungpook National University) ;
  • Jung Jong-Jae (Department of Chemistry, College of Liberal Arts and Science, Kyungpook National University) ;
  • Hwang Jung-Ui (Department of Chemistry, College of Liberal Arts and Science, Kyungpook National University)
  • 발행 : 1974.10.30

초록

종래의 방법으로 고압하에서 전지의 표준기전력 $(E^{\circ})$를 산출하는 것은 불가능하다. 그러나 완전평형상수의 개념을 종래의 Nernst 방정식에 적용하므로서 고압하에서 표준기전력을 구할 수 있게 되었다(완전 Nernst방정식). 더욱이 다른 열역학적 성질 이를테면 수화수의 순변화(k), 용매의 압축을(${\beta}$), 전지반응에서 종래의 해리상수(K) 평형상태에서 표준자유에너지변화(${\Delta}G^{\circ}$) 표준엔탈피변화(${\Delta}H^{\circ}$) 및 표준엔트로피변화($S^{\circ}$) 등을 얻었다. 본 실험에서는 전지의 기전력(E)을 $20{\sim}35^{\circ}C$와 1∼2500 atms 범위에서 측정하였다. 일정한 온도에서 전지의 기전력은 압력이 증가함에 따라 증가하였으며, 일정한 압력에서 온도가 증가함에 따라 역시 증가하였다. 전지반응의 수화수의 순변화(k)는 $20^{\circ}C$에서 41.96으로서 압력에 따라 변하지 않고 일정한 값을 유지하였으나 한편 K와 ${\Delta}S^{\circ}C$는 압력에 따라 증가하였으나 ${\Delta}G^{\circ}$${\Delta}H^{\circ}$는 감소하였다. 고압하에서도 완전 Nernst방정식으로부터 표준기전력을 계산할 수 있으므로 상압에서와 마찬가지로 화학평형론을 취급할 수 있게 되었다

It is unable to derive the standard emf ($E^{\circ}$) of the cell at high pressure from the conventional method. However, when the concept of the complete equilibrium constant($K{\circ})$) is available to the conventional Nernst equation, it is possible to get the standard emf of the cell at high pressure(complete Nernst equation). Moreover, the other thermodynamic properties, such as the net change of solvation number(k), the compressibility of solvent(${\beta}$), ionization constant(K), the standard free energy change(${\Delta}G^{\circ}$), the standard enthalpy change(${\Delta}H^{\circ}$) and the standard entropy change (${\Delta}S^{\circ}$) of the cell reaction at equilibrium state have been also obtained. In this experiment, the emf of the cell; 12.5 % Cd(Hg)│$CdSO_4(3.105{\times}10^{-3}M),\;Hg_2SO_4│Hg$ have bee measured at temperature from 20 to $35^{\circ}C$ and at pressures from 1 to 2500 atms. The emf of the cell increased with increasing pressure at constant temperature, and did with increasing temperature at constant pressure. The net change of solvation number(k) of the cell reaction was 41.96 at $25^{\circ}C$, and kept constant value with pressure, while, K and ${\Delta}S^{\circ}$ increased with pressure, but whereas ${\Delta}G^{\circ}$ and ${\Delta}H^{\circ}$ decreased. Since the standard emf of the cell at high pressure can be calculated from the complete Nernst equation, the theory of chemical equilibrium could be developed with at high pressure as well as at the atmosphere.

키워드

참고문헌

  1. J. Amer. Soc. v.36 G.N. Lewis;M. Randall
  2. J. Amer. Soc. v.38 N.E. Loomis;S. F. Acree
  3. J. Amer. Soc. v.38 J. H. Ellis
  4. Z. Phisk. Chem. v.170A E. Cohen;K. Piepenbroek
  5. The Peview of Scientific Instruments v.33 E. U. Franck;J. E. Savolainen;William L. Marshall
  6. J. Phys. Chem. v.72 Arvin S. Quist;William L. Marshall
  7. J. Phys. Chem. v.76 Leroy B. Yeatts;William L. Marshall
  8. J. Phys. Chem. v.73 Lawrence A Dunn;William L. Marshall
  9. Z. Phys. Chem. (Frankfurt an Main) v.9 Frank
  10. Pros. Natl. Acad. Sci. U.S v.58 W. L. Marshall;A. S. Quist
  11. J. Pyhs. Chem. v.72 A.S. Quist;W.L. Marshall
  12. J. Pyhs. Chem. v.76 W.L. Marshall
  13. J. Pyhs. Chem. v.74 W.L. Marshall
  14. The Principles of Electrochemistry Duncan A. Maclrnnes
  15. Trans. Faraday Soc. v.55 J. Koskikallio;E. Whalley
  16. Trans. Faraday Soc. v.55 B.T. Baliga;E. Whalley
  17. Specific Volume of Liquid Water to 100${\circ}^C$<\TEX>and 1400 bars Properties of Water Part III G.C. Kennedy;W. L. Knight;W.T. Holser
  18. The Specific Volume of Water in the ramge 1,000 to 8,900 bars $20^{\circ}C$<\TEX> to $900^{\circ}C$<\TEX> C. Wayne Buurnham;J. R. Holloway;N.F. Davis