Liquids: Surface Tension, Viscosity, Capillary Action, Vapor Pressure, Boiling Point

Vocabulary flashcards covering core liquid properties and concepts from the lecture notes.

Surface tension

Energy required to increase the surface area of a liquid; a surface property caused by cohesive forces that resists external forces.

Viscosity

A liquid’s internal resistance to flow due to intermolecular friction and cohesive forces.

Capillary action

The ability of a liquid to move up narrow spaces against gravity, driven by adhesive and cohesive forces.

Vapor pressure

The pressure exerted by vapor in equilibrium with its liquid or solid; higher IMF = lower vapor pressure.

Boiling point

The temperature at which a liquid’s vapor pressure equals external atmospheric pressure (usually 1 atm).

Heat of vaporization (molar)

The amount of heat required to vaporize one mole of a substance at its boiling point.

Intermolecular forces (IMF)

Forces between molecules (e.g., hydrogen bonds, dipole-dipole, London dispersion) that influence liquid properties.

Hydrogen bond

A strong type of intermolecular attraction between molecules, typically involving H attached to O, N, or F.

Detergent molecule

A surfactant with a hydrophilic head and a hydrophobic tail that lowers surface tension and emulsifies oils.

Surfactant

A compound that reduces surface tension at interfaces, improving wetting and spreading.

Hydrophobic tail

The nonpolar, water-hating part of a detergent molecule.

Hydrophilic head

The polar, water-loving part of a detergent molecule that interacts with water.

Effects of temperature on surface tension

As temperature increases, surface tension generally decreases due to weakened cohesive forces.

Vaporization

The transition of a substance from a liquid to a gas.

Normal boiling point

The boiling point of a liquid at standard atmospheric pressure (1 atm = 760 mmHg).