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