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Acids and Bases

L recall the colours of phenolphthalein and methyl orange in acidic, alkaline and neutral solutions;
’ describe the effects of acidic, alkaline and neutral solutions on indicator papers (red and blue litmus papers and universal indicator paper) and the use of a pH meter to give pH data to at least one decimal place;
l interpret given data about universal indicator (colour or pH) to classify solutions as acidic, alkaline or neutral and to indicate the relative strengths of acidic and alkaline solutions according to the following classification:
•    pH 0-2 strong acid;
•    pH 3-6 weak acid;
•    pH 7 neutral;
•    pH 8-11 weak alkali; and
•    pH 12-14 strong alkali;
l

demonstrate knowledge and understanding that acids dissolve in water to produce hydrogen ions;

recall that the higher the concentration of hydrogen ions in an acidic solution, the lower the pH;

demonstrate knowledge and understanding that alkalis dissolve in water to produce hydroxide ions;
demonstrate knowledge and understanding that strong acids and strong alkalis are completely ionised in water, recall examples of strong acids (including hydrochloric acid, sulfuric acid and nitric acid) and recall examples of strong alkalis (including sodium hydroxide and potassium hydroxide); and
demonstrate knowledge and understanding that weak acids and weak alkalis are partially ionised in water,
recall examples of weak acids (including ethanoic acid and carbonic acid) and recall examples of weak alkalis (including ammonia).

explain dilute and concentrated in terms of the amount of substances in solution;
describe neutralisation as the reaction between the hydrogen ions in an acid and the hydroxide ions in an alkali to produce water and recall the ionic equation

 The temperature change during neutralisation and demonstrate understanding that neutralisation reactions are exothermic (heat is given out);

recall that a base is a metal oxide or hydroxide which neutralises an acid to produce a salt and water and that an alkali is a soluble base;
i demonstrate knowledge and understanding of and write observations on and equations for the general reactions of hydrochloric, sulfuric and nitric acids with:
•    metals;
•    bases;
•    carbonates;
•    hydrogencarbonates; and
•    ammonia;

describe how to test for hydrogen gas: apply a lighted splint and a popping sound results;S describe how to test for carbon dioxide: limewater (calcium hydroxide solution) will change from colourless to milky if the test is positive; and

demonstrate knowledge and understanding that a salt is a compound formed when some or all of the hydrogen ions in an acid are replaced by metal ions or ammonium ions.

demonstrate knowledge and understanding that most Group 1 (I), Group 2 (II), aluminium and zinc salts are white and if they dissolve in water they give colourless solutions, and that transition metal salts are generally coloured;
demonstrate knowledge and understanding of how pure dry samples of soluble salts can be prepared by:
•    adding excess insoluble substances to acid;
•    adding alkali to acid, or vice versa, in the presence of an indicator; and
•    repeating without indicator or removing the indicator using charcoal
(methods of drying to include placing in a desiccator or a low temperature oven or drying between two sheets of filter paper);

develop awareness of the importance of safety in the laboratory to assess potential risks, including the hazards associated with chemicals labelled with the GHS/CLP international chemical hazard labelling (including toxic, corrosive, flammable, explosive and caution);

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