15.3: Appendix C- Symbols for Physical Quantities
This appendix lists the symbols for most of the variable physical quantities used in this e-book. The symbols are those recommended in the IUPAC Green Book (Ian Mills et al, Quantities, Units and Symbols in Physical Chemistry , 2nd edition, Blackwell, Oxford, 1993) except for quantities followed by an asterisk (\(^*\)). The first table lists Roman letter symbols, and the second lists Greek letter symbols.
\begin{array}{lll} \hline \textbf{Symbol} & \textbf{Physical quantity} & \textbf{SI unit} \\ \hline A & \tx{Helmholtz energy} & \tx{J} \\ \As & \tx{surface area} & \tx{m}^2 \\ a & \tx{activity} & \tx{(dimensionless)} \\ B & \tx{second virial coefficient} & \tx{m}^3 \tx{ mol}^{-1} \\ C & \tx{number of components}^* & \tx{(dimensionless)} \\ C_p & \tx{heat capacity at constant pressure} & \tx{J K}^{-1} \\ C_V & \tx{heat capacity at constant volume} & \tx{J K}^{-1} \\ c & \tx{concentration} & \tx{mol m}^{-3} \\ E & \tx{energy} & \tx{J} \\ & \tx{electrode potential} & \tx{V} \\ \boldsymbol{E} & \tx{electric field strength} & \tx{V m}^{-1} \\ E\cell & \tx{cell potential} & \tx{V} \\ \Ej & \tx{liquid junction potential} & \tx{V} \\ E\sys & \tx{system energy in a lab frame} & \tx{J} \\ F & \tx{force} & \tx{N} \\ & \tx{number of degrees of freedom}^* & \tx{(dimensionless)} \\ \fug & \tx{fugacity} & \tx{Pa} \\ g & \tx{acceleration of free fall} & \tx{m s}^{-2} \\ G & \tx{Gibbs energy} & \tx{J} \\ h & \tx{height, elevation} & \tx{m} \\ H & \tx{enthalpy} & \tx{J} \\ \boldsymbol{H} & \tx{magnetic field strength} & \tx{A m}^{-1} \\ I & \tx{electric current} & \tx{A} \\ I_m & \tx{ionic strength, molality basis} & \tx{mol kg}^{-1} \\ I_c & \tx{ionic strength, concentration basis} & \tx{mol m}^{-3} \\ K & \tx{thermodynamic equilibrium constant} & \tx{(dimensionless)} \\ K\subs{a} & \tx{acid dissociation constant} & \tx{(dimensionless)} \\ K_p & \tx{equilibrium constant, pressure basis} & \tx{Pa}^{\sum\nu} \\ K\subs{s} & \tx{solubility product} & \tx{(dimensionless)} \\ \kHi & \tx{Henry’s law constant of species }i, \\ & \quad \tx{mole fraction basis} & \tx{Pa} \\ k_{c,i} & \tx{Henry’s law constant of species }i, \\ & \quad \tx{concentration basis}^* & \tx{Pa m}^3\tx{ mol}^{-1} \\ k_{m,i} & \tx{Henry’s law constant of species }i, \\ & \quad \tx{molality basis}^* & \tx{Pa kg mol}^{-1} \\ l & \tx{length, distance} & \tx{m} \\ L & \tx{relative partial molar enthalpy}^* & \tx{J mol}^{-1} \\ M & \tx{molar mass} & \tx{kg mol}^{-1} \\ \boldsymbol{M} & \tx{magnetization} & \tx{A m}^{-1} \\ M\subs{r} & \tx{relative molecular mass (molecular weight)} & \tx{(dimensionless)} \\ m & \tx{mass} & \tx{kg} \\ m_i & \tx{molality of species }i & \tx{mol kg}^{-1} \\ N & \tx{number of entities (molecules, atoms, ions,} \\ & \quad \tx{formula units, etc.)} & \tx{(dimensionless)} \\ n & \tx{amount of substance} & \tx{mol} \\ P & \tx{number of phases}^* & \tx{(dimensionless)} \\ p & \tx{pressure} & \tx{Pa} \\ & \tx{partial pressure} & \tx{Pa} \\ \boldsymbol{P} & \tx{dielectric polarization} & \tx{C m}^{-2} \\ Q & \tx{electric charge} & \tx{C} \\ Q\sys & \tx{charge entering system at right conductor}^* & \tx{C} \\ Q\subs{rxn} & \tx{reaction quotient}^* & \tx{(dimensionless)} \\ q & \tx{heat} & \tx{J} \\ R\el & \tx{electric resistance}^* & \Omega \\ S & \tx{entropy} & \tx{J K}^{-1} \\ s & \tx{solubility} & \tx{mol m}^{-3} \\ & \tx{number of species}^* & \tx{(dimensionless)} \\ T & \tx{thermodynamic temperature} & \tx{K} \\ t & \tx{time} & \tx{s} \\ & \tx{Celsius temperature} & \degC \\ U & \tx{internal energy} & \tx{J} \\ V & \tx{volume} & \tx{m}^3 \\ v & \tx{specific volume} & \tx{m}^3\tx{ kg}^{-1} \\ & \tx{velocity, speed} & \tx{m s}^{-1} \\ w & \tx{work} & \tx{J} \\ & \tx{mass fraction (weight fraction)} & \tx{(dimensionless)} \\ w\el & \tx{electrical work}^* & \tx{J} \\ w' & \tx{nonexpansion work}^* & \tx{J} \\ x & \tx{mole fraction in a phase} & \tx{(dimensionless)} \\ & \tx{Cartesian space coordinate} & \tx{m} \\ y & \tx{mole fraction in gas phase} & \tx{(dimensionless)} \\ & \tx{Cartesian space coordinate} & \tx{m} \\ Z & \tx{compression factor (compressibility factor)} & \tx{(dimensionless)} \\ z & \tx{mole fraction in multiphase system}^* & \tx{(dimensionless)} \\ & \tx{charge number of an ion} & \tx{(dimensionless)}\\ & \tx{electron number of cell reaction} & \tx{(dimensionless)} \\ & \tx{Cartesian space coordinate} & \tx{m} \\ \hline \end{array}
\begin{array}{lll} \hline \textbf{Symbol} & \textbf{Physical quantity} & \textbf{SI unit} \\ \hline \alpha & \tx{degree of reaction, dissociation, etc.} & \tx{(dimensionless)} \\ & \tx{cubic expansion coefficient} & \tx{K}^{-1} \\ \g & \tx{surface tension} & \tx{N m}^{-1}, \tx{J m}^{-2} \\ \g_i & \tx{activity coefficient of species i,} \\ & \quad \tx{pure liquid or solid standard state}^* & \tx{(dimensionless)} \\ \g_{m,i} & \tx{activity coefficient of species i,} \\ & \quad \tx{molality basis} & \tx{(dimensionless)} \\ \g_{c,i} & \tx{activity coefficient of species i,} \\ & \quad \tx{concentration basis} & \tx{(dimensionless)} \\ \g_{x,i} & \tx{activity coefficient of species i,} \\ & \quad \tx{mole fraction basis} & \tx{(dimensionless)} \\ \g_{\pm} & \tx{mean ionic activity coefficient} & \tx{(dimensionless)} \\ \G & \tx{pressure factor (activity of a reference state)}^* & \tx{(dimensionless)} \\ \epsilon & \tx{efficiency of a heat engine} & \tx{(dimensionless)} \\ & \tx{energy equivalent of a calorimeter}^* & \tx{J K}^{-1} \\ \vartheta & \tx{angle of rotation} & \tx{(dimensionless)} \\ \kappa & \tx{reciprocal radius of ionic atmosphere} & \tx{m}^{-1} \\ \kappa _T & \tx{isothermal compressibility} & \tx{Pa}^{-1} \\ \mu & \tx{chemical potential} & \tx{J mol}^{-1} \\ \mu\subs{JT} & \tx{Joule–Thomson coefficient} & \tx{K Pa}^{-1} \\ \nu & \tx{number of ions per formula unit} & \tx{(dimensionless)} \\ & \tx{stoichiometric number} & \tx{(dimensionless)} \\ \nu_+ & \tx{number of cations per formula unit} & \tx{(dimensionless)} \\ \nu_- & \tx{number of anions per formula unit} & \tx{(dimensionless)} \\ \xi & \tx{advancement (extent of reaction)} & \tx{mol} \\ \varPi & \tx{osmotic pressure} & \tx{Pa} \\ \rho & \tx{density} & \tx{kg m}^{-3} \\ \tau & \tx{torque}^* & \tx{J} \\ \phi & \tx{fugacity coefficient} & \tx{(dimensionless)} \\ & \tx{electric potential} & \tx{V} \\ \Del\phi & \tx{electric potential difference} & \tx{V} \\ \phi_m & \tx{osmotic coefficient, molality basis} & \tx{(dimensionless)} \\ \varPhi_L & \tx{relative apparent molar enthalpy of solute}^* & \tx{J} mol^{-1} \\ \omega & \tx{angular velocity} & \tx{s}^{-1} \\ \hline \end{array}