5.3 Physical Properties of Liquids Flashcards

Vocabulary-style flashcards covering the physical properties of liquids including evaporation, vapour pressure, boiling point, and vacuum distillation as described in the Chapter 5 lecture notes.

Evaporation

The spontaneous change of a liquid into its vapours at any temperature.

Vaporization (Kinetic Molecular Theory)

The process where molecules with greater kinetic energy move faster, reach the surface, and escape into vapours.

Vapour pressure

The pressure exerted by the vapours of the liquid when the rate of evaporation becomes equal to the rate of condensation.

Dynamic Equilibrium

A state established in a closed container when the rate of evaporation is equal to the rate of condensation.

Barometer

An instrument consisting of a long glass tube used to measure vapour pressure and atmospheric pressure.

One atmospheric pressure

The atmospheric condition that can hold mercury at a height of $760\,mmHg$ or $76\,cm\,Hg$ at sea level at $273.15\,K$ temperature.

Boiling point

The temperature at which the vapour pressure of a liquid becomes equal to the atmospheric pressure or some other external pressure.

Pressure Cooker

A closed container where heating builds up vapour pressure to increase the boiling point of water, allowing food to cook faster.

Boiling point of water at Mount Everest

At an external pressure of $0.425\,atm$, water boils at $72^{\circ}C$.

Boiling point of water at Murree Hills

At an external pressure of $0.921\,atm$, water boils at $98^{\circ}C$.

Vacuum distillation

Distillation carried out under reduced pressure, which lowers the boiling point of liquids to avoid thermal decomposition.

Glycerine purification

A process where the boiling point is reduced from $290^{\circ}C$ at $1\,atm$ to $210^{\circ}C$ at $50\,mmHg$ to avoid decomposition.

Thermal decomposition

The process where high boiling point liquids break down before reaching their normal boiling point at $1\,atm$.