Kinetic model of matter
● In this model, the things that are moving are the particles of which matter is made
● Melting → It is the process in which a solid changes to a liquid.
● Freezing → It is the process in which a liquid changes to a solid
● Evaporation → It is the process in which a liquid changes to a gas
● Condensation → It is the process in which a gas changes to a liquid
● Sublimation → It is the process in which a solid changes directly into a gas without going to the
liquid state
● Deposition → It is the process in which a gas changes to a solid directly
● Melting point → It is the temperature at which a solid changes to a liquid state
● Boiling point → It is the temperature at which a liquid changes to a gas state
Brownian motion -
It is the random motion of particles
suspended in a medium
● Solids
○ In solids the particles are highly packed
○ Forces of attraction between the particles are strong. Less intermolecular spaces between
the particles.
○ Definite shape/volume and high density. Cannot be compressed
● Liquids
○ Particles loosely packed. Forces of attraction are less than of solid
○ Definite volume and density. No definite shape, it depends on the shape of the container
○ Slightly compressible. Particles are always in a random motion (Brownian motion)
● Gases
○ Particles are very loosely packed very weak forces of attraction between particles. Less
intermolecular spaces between the particles.
○ No definite shape or volume, low density. Highly compressible
● Factors affecting evaporation
○ Temperature (direct)
○ Surface area(direct)
○ Humidity (indirect)
○ Wind speed (direct)
● Boyle’s law
○ It states that the volume of a fixed mass of gas is inversely proportional to its pressure
of constant temperature
○ pV = K (temperature)
○ p1V1 = p2V2
● Charle’s law
○ The volume and absolute temperature (K) of a gas are directly proportional
○ At constant mass and pressure
○ V1/T1 = V2/T2
● Gay-Lussacs law
○ The pressure and absolute temperature of a gas are directly proportional
○ At constant mass and volume
○ p1/T1 = p2/T2
● Combined gas law
○ p1V1/T1 = p2V2/T2
