네른스트 식. Cu | Cu^2+ (0.0200 M) || Ag^+ (0.0200 M) | Ag

네른스트 식. Cu | Cu^2+ (0.0200 M) || Ag^+ (0.0200 M) | Ag

 

 

다음 전지에 대한 전위를 계산하시오.

Cu | Cu^2+ (0.0200 M) || Ag^+ (0.0200 M) | Ag

> Ag^+ + e^- → Ag(s) ... E° = +0.799 V

> Cu^2+ + 2e^- → Cu(s) ... E° = +0.337 V

 

---------------------------------------------------

 

> 산화: Cu → Cu^2+ + 2e^-

> 환원: 2Ag^+ + 2e^- → 2Ag

 

> 전체: Cu + 2Ag^+ → Cu^2+ + 2Ag

Q = [Cu^2+] / [Ag^+]^2

 

 

 

E°_cell = E°_red – E°_red

= (환원된 물질의 표준환원전위) – (산화된 물질의 표준환원전위)

( 참고 https://ywpop.tistory.com/4558 )

 

= (+0.799) – (+0.337) = +0.462 V

 

 

 

Nernst 식

E = E° – (0.0592 V / n) × logQ

( 참고 https://ywpop.tistory.com/2900 )

 

= (+0.462) – (0.0592 / 2) × log(0.0200 / 0.0200^2)

= +0.412 V

 

 

 

답: +0.412 V

 

 

 

 

[ 관련 예제 https://ywpop.tistory.com/5351 ] 네른스트 식. Cu^2+(aq) + 2Ag(s)

 

 

 

[키워드] Cu | Cu^2+ || Ag^+ | Ag, Cu(s) | Cu^2+(aq) || Ag^+(aq) | Ag(s), Cu(s) + 2Ag^+(aq) → Cu^2+(aq) + 2Ag(s)