Who's been cheating on the vinegar?
Aim:
To investigate if the vinegars have been diluted by working out their concentrations.
Scientific Background:
Vinegar is an acid and there fore can be neutralised by an alkali.
Acid + Alkali à salt + water
Hydrochloric acid + Sodium Hydroxide à Sodium chloride + water
Vinegar is a weak acid and therefore it only partially ionises in solution.
CH3COOH ßà CH3COO- + H+
An alkali such as Sodium Hydroxide has a formula NaOH. If the alkali is strong then it ionises fully in solution.
NaOH ßà Na+ + OH-
When the acid H+ reacts with the alkali OH- the solution neutralises.
Prediction:
If the acid has been diluted there will be less H+ ions present in the volume used. Therefore to cancel the alkali more acid will be required. This is on the assumption that the alkali volume and concentration stay constant.
Method:
· Measure 10cm3 of 0.1m alkali into a measuring cylinder then place the solution into......
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