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
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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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How to calculate enthalpy of neutralisation
Determining either the enthalpy change of neutralisation, or the enthalpy change for a classic displacement reaction (they are pretty much
How to calculate enthalpy of combustion of a fuel
You can calculate an experimental value for the enthalpy change of combustion for a fuel very simply – this is
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Getting up to speed in thermochemistry
Thermochemistry is all about the energy changes that happen alongside chemical reactions. Chemical reactions either release heat (exothermic) or
How to choose an indicator for an acid-base titration
An indicator is used to follow the progress of an acid-base titration and the end point of the reaction is
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How to explain the shape of a titration curve
1. Strong acid – strong base titrations Imagine we are titrating a strong acid such as hydrochloric acid against a
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What is a buffer and how do I calculate its pH?
A buffer is defined as a solution that is able to resist changes in pH when small amounts of acid
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How to calculate the pH of a base
Once again, we can assume that strong bases are fully dissociated in solution so the concentration of OH– is the
How to calculate the pH of strong acids and weak acids
The strength of an acid (HA) is determined by its ability to donate protons or H+ ions to water. The [H+(aq)]
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What is the ionic product of water?
Water self-ionises – essentially it reacts with itself to very small extent. We know this because even pure water has