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→Key Stage 4
===About Exothermic Processes===
====Foundation====
: [[Exothermic]] [[Chemical Reaction|reactions]] usually require [[energy]] to begin. This is called the [[Activation Energy|activation energy]].
: In an [[exothermic]] process the [[Potential Energy|potential energy]] stored in the [[product]]s is less than the [[Potential Energy|potential energy]] stored in the [[reactant]]s.
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| style="height:20px; width:500px; text-align:center;" |To start the [[Chemical Reaction|reaction]] an [[Activation Energy|activation energy]] is needed. This is usually achieved by initially [[heating]] the [[reactant]]s. Once the [[Chemical Reaction|reaction]] starts the [[energy]] stored in the [[reactant]]s is released in the [[Chemical Reaction|chemical reaction]] making the [[material]] increase in [[temperature]]. The [[product]]s now have less [[energy]] than the [[reactant]]s.
|}
====Higher====
: In a [[Chemical Reaction|chemical reaction]] [[energy]] is needed to break the [[Chemical Bond|chemical bonds]] holding the [[atom]]s together.
: In an [[exothermic]] [[Chemical Reaction|reaction]] [[energy]] is them released as [[atom]]s form new [[Chemical Bond|chemical bonds]].
: This happens because there is less [[energy]] stored in the [[Chemical Bond|chemical bond]]s of the [[product]]s than the [[reactant]]s.
===Examples===
====Higher====
{| class="wikitable"
|-
| style="height:20px; width:200px; text-align:center;" |Bond
| style="height:20px; width:200px; text-align:center;" |Energy in kJ/mol
|-
| style="height:20px; width:200px; text-align:center;" |C-H
| style="height:20px; width:200px; text-align:center;" |413
|-
| style="height:20px; width:200px; text-align:center;" |O=O
| style="height:20px; width:200px; text-align:center;" |498
|-
| style="height:20px; width:200px; text-align:center;" |O-H
| style="height:20px; width:200px; text-align:center;" |464
|-
| style="height:20px; width:200px; text-align:center;" |C=O
| style="height:20px; width:200px; text-align:center;" |799
|}