activity coefficient \(f\), \(\gamma \)

https://doi.org/10.1351/goldbook.A00116
The activity @C01124@ \(f_{\text{B}}\) of a substance B in a liquid or solid mixture containing @M03980@ fractions \(x_{\text{B}}\), \(x_{\text{C}}\), ... of the substances B, C, ... is a dimensionless quantity defined in terms of the @C01032@ \(\mu _{\text{B}}\) of B in the mixture by: \[R\ T\ \ln (x_{\text{B}}\ f_{\text{B}})=\mu _{\text{B}}\left(\mathrm{cd},T,P,x\right)- \mu _{\text{B}}^{*}\left(\mathrm{cd},T,p\right)\] where \(x\) denotes the set of @M03980@ fractions \(x_{\text{B}}\), \(x_{\text{C}}\), ... . The activity @C01124@ \(\gamma _{\text{B}}\) of a solute B in a solution (especially a dilute liquid solution) containing molalities \(m_{\text{B}}\), \(m_{\text{C}}\), ... of solutes B, C, ... in a solvent A is a dimensionless quantity defined in terms of the @C01032@ \(\mu _{\text{B}}\) by: \[R\ T\ \ln \left(\frac{m_{\text{B}}\ \gamma _{\text{B}}}{m^{\ominus}}\right)=\mu _{\text{B}}- \left\{\mu _{\text{B}}- R\ T\ \ln \left(\frac{m_{\text{B}}}{m^{\ominus }}\right)\right\}^{\infty }\]
Sources:
PAC, 1990, 62, 2167. (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2171 [Terms] [Paper]
PAC, 1994, 66, 533. (Standard quantities in chemical thermodynamics. Fugacities, activities and equilibrium constants for pure and mixed phases (IUPAC Recommendations 1994)) on page 543 [Terms] [Paper]
PAC, 1996, 68, 957. (Glossary of terms in quantities and units in Clinical Chemistry (IUPAC-IFCC Recommendations 1996)) on page 960 [Terms] [Paper]