# States of Matter

solids

liquids

gases

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## solids

have a fixed shape

have a fixed volume

the particles are tightly packed and arranged regularly in fixed positions

the particles are not free to move but the do vibrate around their fixed positions

particles are touching

solids have the lowest energy

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## gases

have no fixed shape

have no fixed volume

particles are far apart

particles move freely and randomly with lots of energy

particles move extremely fast

gases have the most energy because their particles are moving so quickly (speed of a bullet)

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## changes of state

solid -> liquid = melting

liquid -> gas = evaporating

gas -> liquid = condensing

liquid -> solid = freezing

solid -> gas = sublimation

gas -> solid = deposition

interconversions = change of state

going from soild -> liquid -> gas requires energy input

heating ice makes its particles vibrate more vigorously. eventually the bonds between the solid particles are broken and it turns into water. if we heat the water, the particles get even more kinetic energy. some particles move so fast they have enough energy to break away from their neighbours and escape as a gas

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## cooling

going from gas to liquid to solid requires taking energy out. cooling a gas makes its particles start to move more slowly and get closer together as a result. eventually all the particles are touching, and a liquid is formed. as a liquid cools even further, the particles lose more energy, they become fixed in a position (solid)

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## heating

as the temperature of the solid increases, its particles vibrate more vigorously. at the melting point, the temperature doesn't go up; instead the energy put in is going into breaking the bonds holding the particles in their fixed positions. once all the bonds are broken the temperature of the liquid can increase.

the same thing happens at the boiling point; the energy goes into breaking the bonds between the liquid particles.

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## liquids

have a fixed shape

have a fixed volume

particles are touching, loosely arranged, with no fixed positions

liquid particles are in constant, random motion, slipping and sliding past eachother

liquids have a 'middling' amount of energy

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