5.1: Concentration Units 5.2: Partial Molar Quantities 5.3: The Thermodynamics of Mixing 5.4: Binary Mixtures of Volatile Liquids 5.5: Real Solutions A non-ideal solution is a solution that does not abide to the rules of an ideal solution where the interactions between the molecules are identical (or very close) to the interactions between molecules of different components. That is, there is no forces acting between the components: no Van-der-Waals nor any Coulomb forces. We assume ideal properties for dilute solutions. 5.6: Colligative Properties 5.7: Electrolyte Solutions 5.8: Ionic Activity the behavior of an electrolyte solution deviates considerably from that an ideal solution. Indeed, this is why we utilize the activity of the individual components and not the concentration to calculate deviations from ideal behavior. In 1923, Peter Debye and Erich Hückel developed a theory that would allow us to calculate the mean ionic activity coefficient of the solution and could explain how the behavior of ions in solution contribute to this constant. 5.9: Colligative Properties of Electrolyte Solutions 5.10: Biological Membranes 5.11: Solutions (Exercises)