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Physical Chemistry. Chapter 6. Chapter 6. Reaction Equilibrium in Ideal Gas Mixtures. one-phase pure substance. (4.86)*. Physical Chemistry. Chapter 6. Chemical Potentials in an Ideal Gas Mixture. Chemical Potential of a Pure Ideal Gas. (4.36). isothermal, pure ideal gas.
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Physical Chemistry Chapter 6 Chapter 6 Reaction Equilibrium in Ideal Gas Mixtures
one-phase pure substance (4.86)* Physical Chemistry Chapter 6 Chemical Potentials in an Ideal Gas Mixture Chemical Potential of a Pure Ideal Gas (4.36) isothermal, pure ideal gas isothermal, pure ideal gas (6.1) pure ideal gas, Po1 bar (6.2)
- o RT 0 1 2 3 P/Po -RT -2RT Physical Chemistry Chapter 6 Chemical Potentials in an Ideal Gas Mixture For a pure ideal gas Fig. 6.1 T is fixed
Ideal gas mixture at T and P membrane Pure gas mixture at and T Physical Chemistry Chapter 6 Chemical Potentials in an Ideal Gas Mixture An ideal gas mixture (1) (2) The mixture is separated by thermally conducting rigid membrane permeable to gas i only, and ideal gas mixture Fig. 6.2 (6.3)
Ideal gas mixture at T and P No intermolecular interaction, no effect on from other gases in the mixture. membrane Pure gas mixture at and T ideal gas mixture (6.4)* Physical Chemistry Chapter 6 Chemical Potentials in an Ideal Gas Mixture ideal gas mixture (6.3) Fig. 6.2 The fundamental thermodynamic equation
i - io RT 0 1 2 3 Pi/Po -RT -2RT Physical Chemistry Chapter 6 Chemical Potentials in an Ideal Gas Mixture For an ideal gas mixture Fig. 6.1 (modified)
(6.4)* Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium For the ideal-gas reaction (4.36) the equilibrium condition
Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.5) the equilibrium condition
Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.6) (6.7)
(6.7) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium the equilibrium condition (6.8)
Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.9) (6.10) (6.11)*
(6.11)* (6.10) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.12) (6.13)* (6.14)* (6.15)
(6.9) Since depends only on T, for a given ideal-gas reaction is a function of T only. At a given temperature, is constant for a given reaction. (6.15) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium the standard equilibrium constant the standard pressure equilibrium constant
(6.13)* Since is dimensionless, the standard equilibrium constant is dimensionless. (6.19) has dimensions of pressure raised to the change in mole numbers for the reaction as written. Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium the equilibrium constant the pressure equilibrium constant
(6.13)* the molar concentration (6.21)* ideal gas mixture (6.22) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.23)
(6.13)* (6.23) (6.24) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium n/mol same dimension as Po
(6.13)* the standard equilibrium constant the standard pressure equilibrium constant (6.24) the standard equilibrium constant the concentration equilibrium constant Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium
(6.23) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium (6.25) (6.26) (6.27)
(6.31) (6.9) (6.32) Physical Chemistry Chapter 6 van’t Hoff Equation From (6.14)
(6.31) (6.33) (6.34) (6.32) Physical Chemistry Chapter 6 van’t Hoff Equation From
(6.36)* (6.34) (6.32) Physical Chemistry Chapter 6 van’t Hoff Equation
Physical Chemistry Chapter 6 Gibbs-Helmholtz Equation
Physical Chemistry Chapter 6 Gibbs-Helmholtz Equation When it is applied to changes
Physical Chemistry Chapter 6 van’t Hoff Equation From (6.14) Differentiation of lnKPowith respect to temperature gives The differentials are complete because K and G depend only on temperature, not on pressure. Using Gibbs-Helmholtz equation (6.36)*
(6.36)* (6.37) (6.38) (6.39) Physical Chemistry Chapter 6 van’t Hoff Equation
(6.36)* (6.40) Physical Chemistry Chapter 6 van’t Hoff Equation The van’t Hoff equation is an expression for the slope of a graph of the equilibrium constant (specially, lnK) plotted against the temperature. It may be expressed in either of two ways:
the reaction quotient (6.41) the equilibrium constant (6.19) Physical Chemistry Chapter 6 Ideal Gas Reaction Equilibrium The equilibrium extent of reaction The extent of reaction The reaction goes to right The reaction reaches equilibrium The reaction goes to left
Physical Chemistry Chapter 6 Simultaneous Equilibria A system with several simultaneous reactions that have species in common. (6.47) (6.48)
Physical Chemistry Chapter 6 Simultaneous Equilibria At 600 K, CH3Cl(g) and H2O(g) react to form CH3OH, and then form (CH3)2O with a simultaneous equilibrium shown: (1) (2) Starting with equal amount of CH3Cl and H2O, find the equilibrium amounts of all species.
Physical Chemistry Chapter 6 Simultaneous Equilibria Suppose that a system initially contains 1 mole of CH3Cl(g) and H2O(g), x moles of HCl and y moles of (CH3)2O are formed at equilibrium. (1) 1-x 1-x+y x-2y x (2) x-2y y 1-x+y
Physical Chemistry Chapter 6 Simultaneous Equilibria Suppose that a system initially contains 1 mole of CH3Cl(g) and H2O(g), x moles of HCl and y moles of (CH3)2O are formed at equilibrium.
Physical Chemistry Chapter 6 Simultaneous Equilibria The equilibrium amounts of all species are (1) 0.952 0.961 0.03 0.048 (2) 0.03 0.009 0.961