EL 9 

==Acid=== contains hydrogen (H+) ions when dissolved in water. Also known as a proton donor

==Base=== the opposite of an acid. A proton acceptor

==Alkalis=== a base that dissolves in water, contains hydroxide ions (OH-) when dissolved in water

==Neutralisation=== in neuralisation reactions between an acid and an alkali, the hydrogen ions react with hydroxide ions to produce water and a salt

==Oxonium ion=== a reaction between acid and water produces the oxonium ion H3O+

- The lone pair on the O forms a dative covalent bonds to H+

- Water behaves as a base and the oxonium ion can act as an acid

==Concentration=== moles/volume

- Normally in mol/dm^3

We can use how concentration is linked to moles to help determine the concentration of unknown samples. Experimentally we do this by titration

We use titrations to find out the unknown concentration of substances

==Concordant titres=== titration results that are in 0.1cm^3 of each other. The mean of these can then be used in calculations. The titration must be repeated until 2 concordant titres are achieved.

You always have to measure from the bottom of the meniscus

==% error= (uncertainty/volume recorded) times 100==

==Overall % error of practical= % error 1 + % error 2 …==