The ultimate A level chemistry resource
A redox reaction consists of two half reactions – an oxidation and a reduction reaction. If we take a pair
Continue readingPredicting the feasibility of redox reactions using standard electrode potentials
We can link any two half cells together to form an electrochemical cell. A high resistance voltmeter prevents current (electrons)
Continue readingDetermining the potential difference of an electrochemical cell
If we place a strip of a metal such as zinc into a beaker containing zinc sulphate (the electrolyte) an
Often writing a half equation to show reduction or oxidation is straight forward – all we need to do is
Continue readingUsing oxidation states to balance half equations
Redox titration questions are very popular on exam papers. They are usually set in an unfamiliar context and may require
Given two half equations, we need to be able to write a fully balanced redox equation both under acidic and
Continue readingWriting balanced redox equations using half equations
the oxidation state of an element is always zero the sum of the oxidation states of the elements in a
Reactions in which both oxidation and reduction occur are called redox reactions. The acronym OILRIG might be familiar, reminding us
Reactions are either endothermic or exothermic – the heat transferred during a chemical reaction is either moving from the system
Continue readingUsing bond enthalpies to calculate an enthalpy change of reaction
What is enthalpy exactly? An enthalpy change is the heat transferred at constant pressure by a chemical reaction Heat changes
Continue readingEnthalpy cycles, Hess cycles, thermochemical cycles