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Vapor Pressure and Phase Changes
Key Concepts
Vapor Pressure: The pressure exerted by a vapor in thermodynamic equilibrium with its
condensed phases (solid or liquid) at a given temperature.
Phase Changes: Transitions between solid, liquid, and gas phases. These transitions are
influenced by temperature and pressure.
Boiling Point: The temperature at which the vapor pressure of a liquid equals the surrounding
atmospheric pressure.
Clausius-Clapeyron Equation: Relates the vapor pressure of a liquid to temperature. This
equation is used to estimate the vapor pressure at different temperatures.
Explanation
When a liquid is placed in a closed container, some of its molecules escape into the gas phase. The
pressure exerted by these gas molecules is the vapor pressure. As temperature increases, more
molecules escape into the gas phase, leading to a higher vapor pressure.
Phase changes occur when a substance transitions between solid, liquid, and gas states. The energy
required for these transitions involves overcoming intermolecular forces. For example, to melt a solid,
energy is required to disrupt the crystal lattice structure.
Solubility and Henry’s Law
Key Concepts
Solubility: The maximum amount of solute that can dissolve in a given amount of solvent at a
specific temperature.
Henry’s Law: States that the amount of dissolved gas in a liquid is proportional to its partial
pressure above the liquid.
Explanation