Chemistry GCSE Unit 3 Acids and Alkalis 4.0 / 5 based on 2 ratings ? ChemistryGCSEAll boards Created by: Izzy KeighleyCreated on: 14-03-12 20:17 Strong acids Completely ionise in water 100HCl molecules in water would ionise 100% to make H+ and Cl- ions Water has to be present Hydrochloric acid Nitric acid Sulphuric acid 1 of 11 Weak acids Partially ionise in water Generally acids we eat Formulas often end in COOH Water has to be present Ethanoic acid Citric acid Carbonic acid 2 of 11 Bronsted lowry theory A Bronsted Lowry acid is a proton donor A Bronsted Lowry base is a proton acceptor 3 of 11 Common acids Water must be present for them to act as acids e.g dissolved When added to water, the hydrogen ion dissociates from the rest of the acid and is hydrated by the water 4 of 11 Common alkalis Produce OH- ions in water 5 of 11 Strong alkalis Completely ionise in water PH 11-14 6 of 11 Weak alkalis Partially ionise in water E.g. ammonia 7 of 11 Arrhenies' theory An acid was a source of H+ An alkali was a source of OH- This doesn't fit with ammonia Theory replaced by Bronsted Lowry theory 8 of 11 Titrations Measures the volume of acid and alkali needed to neutralise each other Indicator is added to the solution to observe when the reaction has occured 9 of 11 Indicators Phelophthalein Any strong acid with any strong alkali Any weak acid and strong alkali Colour in acid - colourless Colour in alkali - pink Methyl orange Any strong acid and any strong alkali Colour in acid - red Colour in alkali - yellow 10 of 11 Titration calculations moles = vol (cm3) x conc 100 conc = moles / vol 1000 mass = moles x Mr 11 of 11
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