States of Matter
● Atoms are the smallest particles in an element which cannot be broken down further in a chemical
reaction
● Particles which consist of 2 or more atoms joined together are called molecules
● Particles which carry a charge are known as ions
● The random movement of particles in a fluid as a result of continuous collisions with the molecules
of the fluid is called Brownian motion
● Diffusion is the net movement of particles from a region of their higher concentration to a region
of their lower concentration, down a concentration gradient.
● Variables of diffusion
○ Higher temperature → more KE → faster diffusion
○ More concentration
○ Mass of the molecule / relative molecular mass
● Perfume
○ Liquid to gas
○ Gains enough kinetic energy
○ Particles collide → random collisions
○ Diffusion
Solid
● Properties
○ Definite shape and volume
○ Normally hard and rigid
○ Large force required to change shape
○ Incompressible
○ High density
● Model
○ Closely packed
○ Occupy minimum space
○ Regular pattern
○ Vibrate in fixed position
○ Not free to move
Liquid
● Properties
○ Definite volume but no shape
○ High density
○ Not compressible
● Model
○ Occur in clusters with molecules slightly further apart compared to solids
○ Free to move about within confined vessel
Gas
● Properties
○ No fixed volume or shape
○ Low density
○ Highly compressible
● Model
○ Very far apart
○ Travel at high speeds
○ Independant and random motions
○ Negligible/low forces of attraction between them
● When air particles collide with each other they exert pressure the same way gases exert gas
pressure. The pressure depends on the temperature of the gas and the volume it takes up.
● When you heat a gas in a closed container, its pressure increases
● The particles in the gas move fast, they hit walls of the container and exert pressure on them. If
you heat them, they take in the heat energy and move faster. Therefore, hit the walls more often
with more force, therefore has pressure increases
● When a gas is compressed into smaller space, its pressure increases
● There is a lot of space between the particles in a gas. You can compress the gas or force its
particles closer by pushing in the punger, the particles are in a smaller space so they hit walls
more often therefore gas pressure increases
● The lower the mass of the particle the faster a gas will diffuse(relative molecular mass)
● The higher the temperature, the faster a gas will diffuse
