平衡定数

定義

標準平衡定数

${\displaystyle K^{\circ }=\exp \left[-\sum _{i}{\frac {\nu _{i},円\mu _{i}^{\circ }(T)}{RT}}\right]}${\displaystyle K^{\circ }=\exp \left[-\sum _{i}{\frac {\nu _{i},円\mu _{i}^{\circ }(T)}{RT}}\right]}

${\displaystyle K^{\circ }=\prod \left[\lambda _{i}^{\circ }(T)\right]^{-\nu _{i}}}${\displaystyle K^{\circ }=\prod \left[\lambda _{i}^{\circ }(T)\right]^{-\nu _{i}}}

${\displaystyle \nu _{\text{A}}{\text{A}}+\nu _{\text{B}}{\text{B}}\rightleftharpoons \nu _{\text{C}}{\text{C}}+\nu _{\text{D}}{\text{D}}}${\displaystyle \nu _{\text{A}}{\text{A}}+\nu _{\text{B}}{\text{B}}\rightleftharpoons \nu _{\text{C}}{\text{C}}+\nu _{\text{D}}{\text{D}}}

${\displaystyle K^{\circ }={\frac {(\lambda _{\text{A}}^{\circ })^{\nu _{\text{A}}}(\lambda _{\text{B}}^{\circ })^{\nu _{\text{B}}}}{(\lambda _{\text{C}}^{\circ })^{\nu _{\text{C}}}(\lambda _{\text{D}}^{\circ })^{\nu _{\text{D}}}}}}${\displaystyle K^{\circ }={\frac {(\lambda _{\text{A}}^{\circ })^{\nu _{\text{A}}}(\lambda _{\text{B}}^{\circ })^{\nu _{\text{B}}}}{(\lambda _{\text{C}}^{\circ })^{\nu _{\text{C}}}(\lambda _{\text{D}}^{\circ })^{\nu _{\text{D}}}}}}

圧平衡定数

${\displaystyle K_{p}=\prod \left[{\frac {x_{i}p}{p^{\circ }}}\right]^{\nu _{i}}}${\displaystyle K_{p}=\prod \left[{\frac {x_{i}p}{p^{\circ }}}\right]^{\nu _{i}}}

${\displaystyle K_{p}=\left({\frac {x_{\text{C}}p}{p^{\circ }}}\right)^{\nu _{\text{C}}}\left({\frac {x_{\text{D}}p}{p^{\circ }}}\right)^{\nu _{\text{D}}}{\bigg /}\left({\frac {x_{\text{A}}p}{p^{\circ }}}\right)^{\nu _{\text{A}}}\left({\frac {x_{\text{B}}p}{p^{\circ }}}\right)^{\nu _{\text{B}}}}${\displaystyle K_{p}=\left({\frac {x_{\text{C}}p}{p^{\circ }}}\right)^{\nu _{\text{C}}}\left({\frac {x_{\text{D}}p}{p^{\circ }}}\right)^{\nu _{\text{D}}}{\bigg /}\left({\frac {x_{\text{A}}p}{p^{\circ }}}\right)^{\nu _{\text{A}}}\left({\frac {x_{\text{B}}p}{p^{\circ }}}\right)^{\nu _{\text{B}}}}

${\displaystyle K_{p}=\prod \left[{\frac {f_{i}(x;T,p)}{p^{\circ }}}\right]^{\nu _{i}}}${\displaystyle K_{p}=\prod \left[{\frac {f_{i}(x;T,p)}{p^{\circ }}}\right]^{\nu _{i}}}

濃度平衡定数

${\displaystyle K_{c}=\prod \left[{\frac {c_{i}}{c^{\circ }}}\right]^{\nu _{i}}}${\displaystyle K_{c}=\prod \left[{\frac {c_{i}}{c^{\circ }}}\right]^{\nu _{i}}}

${\displaystyle K_{c}=\left({\frac {c_{\text{C}}}{c^{\circ }}}\right)^{\nu _{\text{C}}}\left({\frac {c_{\text{D}}}{c^{\circ }}}\right)^{\nu _{\text{D}}}{\bigg /}\left({\frac {c_{\text{A}}}{c^{\circ }}}\right)^{\nu _{\text{A}}}\left({\frac {c_{\text{B}}}{c^{\circ }}}\right)^{\nu _{\text{B}}}}${\displaystyle K_{c}=\left({\frac {c_{\text{C}}}{c^{\circ }}}\right)^{\nu _{\text{C}}}\left({\frac {c_{\text{D}}}{c^{\circ }}}\right)^{\nu _{\text{D}}}{\bigg /}\left({\frac {c_{\text{A}}}{c^{\circ }}}\right)^{\nu _{\text{A}}}\left({\frac {c_{\text{B}}}{c^{\circ }}}\right)^{\nu _{\text{B}}}}

${\displaystyle K_{c}=\prod \left[a_{c,i}(c;T,p)\right]^{\nu _{i}}}${\displaystyle K_{c}=\prod \left[a_{c,i}(c;T,p)\right]^{\nu _{i}}}

定義に関する注意

化学平衡

${\displaystyle \Delta _{\text{r}}G^{\circ }=\sum _{i}\nu _{i}\mu _{i}^{\circ }}${\displaystyle \Delta _{\text{r}}G^{\circ }=\sum _{i}\nu _{i}\mu _{i}^{\circ }}

${\displaystyle K^{\circ }=\exp \left[-{\frac {\Delta _{\text{r}}G^{\circ }}{RT}}\right]}${\displaystyle K^{\circ }=\exp \left[-{\frac {\Delta _{\text{r}}G^{\circ }}{RT}}\right]}

${\displaystyle K^{\circ }=K_{p}}${\displaystyle K^{\circ }=K_{p}}

${\displaystyle K^{\circ }=K_{c}}${\displaystyle K^{\circ }=K_{c}}

脚注

出典

1. ^ 『学術用語集 物理学編』
2. ^ IUPAC Goldbook
3. ^ JIS Z 8000-9 2022.
4. ^ "平衡定数・会合定数・解離定数・結合定数について分かりやすく解説". 2019年10月4日閲覧。

参考文献

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