Raoulttörvényhez

Raoulttörvényhez, also known as Raoult's Law, is a fundamental principle in physical chemistry that describes the colligative properties of solutions. Specifically, it relates the vapor pressure of a solution to the vapor pressure of the pure solvent and the mole fraction of the solute. The law states that the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution, provided that the solute is non-volatile and does not dissociate.

Mathematically, Raoult's Law can be expressed as P_solution = X_solvent * P°_solvent, where P_solution is the vapor pressure of the solution, X_solvent is the mole fraction of the solvent in the solution, and P°_solvent is the vapor pressure of the pure solvent. This relationship holds true for ideal solutions, where the interactions between solvent-solvent, solute-solute, and solvent-solute molecules are similar.

Deviations from Raoult's Law occur in real solutions due to non-ideal interactions. Solutions that exhibit positive deviations have a vapor pressure higher than predicted by the law, indicating weaker interactions between solute and solvent molecules than between pure solvent molecules. Conversely, solutions with negative deviations have a vapor pressure lower than predicted, suggesting stronger intermolecular attractions. Raoult's Law is crucial for understanding and calculating properties like boiling point elevation, freezing point depression, and osmotic pressure, which are directly influenced by the vapor pressure lowering.