Chemical Thermodynamics Chemical Potential: gas Need chemical - PowerPoint PPT Presentation

Chemical Thermodynamics

Chemical Potential: gas Need chemical potential at arbitrary temperature  and pressure. For an ideal gas:  Chemical Thermodynamics CEM 484 2

Chemical Potential: liquid Liquids are a little more complicated.  Start by looking at a mixture of two different liquids.  Molar volumes:  Chemical Thermodynamics CEM 484 3

Gibbs-Duhem equation Total Gibbs energy  Two different expressions for dG.  Results in Gibbs-Duhem equation  Chemical Thermodynamics CEM 484 4

Partial molar quantities We will consider many different partial molar  quantities. Total quantity  Partial molar quantity  Sums of partial molar quantities  Chemical Thermodynamics CEM 484 5

Partial molar volume Partial molar volume can be determined  experimentally. Fitting a polynomial to a curve of total volume  versus molality. Chemical Thermodynamics CEM 484 6

Partial molar volume Given a binary liquid mixture knowing the partial  molar volume of one component gives the other. Chemical Thermodynamics CEM 484 7

Chemical potential For a pure substance in equilibrium liquid and gas  chemical potentials are equivalent. Chemical Thermodynamics CEM 484 8

Chemical potential Back to a liquid mixture.  The chemical potentials for a given component in  solution and gas phase are equal. Chemical Thermodynamics CEM 484 9

Chemical potential Chemical potentials of the two components are  related. Chemical Thermodynamics CEM 484 10

Vapor pressure diagram For an ideal solution of two volatile liquids  P-X diagram of an ideal binary solution.  Chemical Thermodynamics CEM 484 11