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: When a [[solid]] [[subliming|sublimates]] [[energy]] is needed to break the [[bond]]s holding the [[particle]]s in fixed positions and keeping the [[particle]]s together.
*[[Freezing]], [[Condensing]] and [[Depositing]] are [[exothermic]] changes because it releases [[energy]] when it happens. The [[material]] has less [[after]] it has happened.
: When a [[gas]] [[condensing|condenses]] [[energy]] is released as [[bond]]s form between adjacent [[molecule]]s to hold them together.
: When a [[liquid]] [[freezing|freezes]] [[energy]] is released as [[bond]]s form between adjacent [[molecule]]s to keep them in fixed positions.
===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 enough [[Potential Energy|potential energy]] to break the . This is an [[bondendothermic]]s holding them in fixed positions the process because it needs [[substanceenergy]] becomes a .: When [[liquidbond]].: When the s are formed between [[particle]]s in a [[gas]] or a [[liquid]] gain enough the [[particle]]s lose [[Potential Energy|potential energy]] to break the [[bond]]s keeping them together the . This is an [[substanceexothermic]] becomes a process because [[gasenergy]]is given off.
====Edexcel====