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Changes
→Key Stage 4
===About State Changes===
: '''State changes''' are [[reversible]] because after a '''state change''' the [[material]] can be returned to its original form with the same [[property|properties]] as it started with.
: '''State changes''' happen when a [[substance]] gains enough [[energy]] to break the [[bond]]s holding [[particle]]s together or loses enough [[energy]] for [[bond]]s to form between [[particle]]s.
: When the [[bond]]s between [[particle]]s in a [[solid]] or a [[liquid]] are broken the [[particle]]s gain [[Potential Energy|potential energy]]. This is an [[endothermic]] process because it needs [[energy]].
: When [[bond]]s are formed between [[particle]]s in a [[gas]] or a [[liquid]] the [[particle]]s lose [[Potential Energy|potential energy]]. This is an [[exothermic]] process because [[energy]] is given off.