Chapter 9 Solutions position Solutions ()* A solution is a homogeneous mixture; that is, a solution is a one-phase system with more than ponent. The mole fraction xi of species i is defined by () The (molar) concentration (or volume concentration) ci of species i is defined by The mass concentration i of species i in a solution of volume V is defined by ()* Physical Chemistry position Solutions The molarity is the molar concentration of a species for liquid solutions in moles per liter (dm3). The molarity mi of species i in a solution is defined by The solute molarity mB is ()* Solution Solvent (A) Solute (B) () Physical Chemistry Partial Molar Quantities Solutions The star indicates a property of a pure substance or a collection of pure substances. () Partial Molar Volumes 0 25 50 75 100 V (ethanol)/cm3 100 99 98 97 96 75 50 25 0 V (H2O)/cm3 V /cm3 Addition of cm3 of water to cm3 of ethanol at 20 oC and 1 atm gives a solution of cm3 (Fig. , left). Physical Chemistry Partial Molar Quantities Solutions 0 25 50 75 100 V (ethanol)/cm3 100 99 98 97 96 75 50 25 0 V (H2O)/cm3 V /cm3 (1) different intermolecular forces (2) different packing of molecules (different sizes and shapes of the molecules being mixed) () The total differential of V () Physical Chemistry Partial Molar Quantities Solutions () The partial molar volume ()* Physical Chemistry nj: the amount of a substance j nij: the amount of all other substances present are constant Partial Molar Quantities Solutions The partial molar volume ()* () Equation () es Physical Chemistry V(a) V(b) x V The partial molar volume is the slope of the graph of the total volume as the amount of j is changed, P, T, amount of ponents being constant Partial Molar Quantities Solutions The partial molar volume ()* The partial molar volume of a pure substance is equal to its molar volume. (
