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Electrophilic aromatic substitution ( S E Ar ) is an organic reaction in which an atom that is attached to an aromatic system (usually hydrogen) is replaced by an electrophile. An electrophile is reagent tha...

An Atom is made up of 3 parts, protons, neutrons and electrons . Each element has it's own number of protons and electrons which will always be the same number . The protons and neutrons make up the nucleus ...

In GCSE history, one of the things they are testing you on is your ability to communicate your knowledge and thoughts under time pressure. With the right approach and enough planning ahead, it easy to get do...

Historiography is the essentially ‘the history of history’. In the typical study of history you will be looking at events and facts- analysing why they happened and the causes and consequences. Historiograph...

To work out simultaneous equations, the aim is to remove one letter from the equations, i.e. Remove the y's so you have only x's and numbers (or vice versa). One way to do this is to get the coefficient in f...