States Of Matter Essay, Research Paper

Kinetic Theory ?

All matter is made up of particles which are in constant motion. Solids ·

Fixed shape and volume ·

Particles are held together by relatively strong

forces, and are incompressible ·

Particles do not have free movement, but can

vibrate about fixed positions ·

An increase in temperature will give the particles

more energy, the amplitude of vibration increases, therefore the solid expands Liquids ·

No fixed shape, but a fixed volume ·

Particles are further apart (due to weaker

forces), so there is slight compressibility ·

Forces are present between particles, but weaker

than in solid so particles can move throughout the bulk of the liquid Gases ·

No fixed shape or volume ·

Particles are very far apart, so are easy to compress ·

Intermolecular forces are negligible, but do

exist. Particles move in a random fashion. Diffusion Diffusion is the process by which a gas fills all

the space available to it. Gases will diffuse (mix with each other) because the

particle are moving randomly and quickly in all directions. Lighter particles

diffuse quicker than heavier particles. evaporation melting boiling SOLID LIQUID GAS freezing condensation sublimation Changes from solid to liquid to gas are

endothermic processes Changes from gas to liquid to solid are exothermic

processes If energy is

supplied to a solid, its particles will vibrate more. If they vibrate enough,

they may separate from each other and become free to move. This is called

melting. At the melting point, energy goes into breaking forces between the

particles, and so there is no temperature increase. The temperature at which

the solid melts is called the melting point. Heating a liquid

makes the particles move faster. At evaporation, some molecules move faster

than others and have more energy, so they overcome the forces of attraction. If

the temperature is increased further, the kinetic energy of the particles

increases until the boiling point, when the forces between the particles are

almost completely broken. At the boiling point energy goes into breaking the

forces between the particle, and so there is no temperature increase. For an impure

sample the melting point is lowered and the boiling point is raised.