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Acids and bases
acids and alkalis indicators : can tell whether it's an acid or alkali
pH scale from 0- acids: less than 7 neutral substances: exactly 7 alkalis: more than 7
universal indicator paper a mixture of dyes only can show whole number pH strong/weak acids and alkalis solutions of acids contain hydrogen ions the higher concentration of hydrogen ions, the lower the pH strong-high conductivity
solutions of alkalis contain hydroxide ions the higher concentration of hydroxide ions, the lower the pH strong-very corrosive
the reactions of acids/alkalis acids: with metals: produce salts and hydrogen with bases:produce salts and water-neutralisation with carbonates:produce carbon dioxide, water and salts bases: with acids:produce salts and water-neutralisation bases such as sodium, potassium and calcium hydroxides react with ammonium salts, driving out ammonia gas neutralisation not a type of Redox reactions react with acids to give off a salt and water-e.g.acids and carbonates, acids and bases real-life application of neutralisation: acidic soil-treated with crushed limestone:slaked lime(CaOH) or lime(CaO) two types of neutralisation: with soluble bases(alkalis) with insoluble bases ionic equations for them: (protons: hydrogen ions)
acids:proton donors bases:proton acceptors oxides definition:compounds that contain oxygen and another element basic oxides in general metals react with oxygen they belongs to bases
making insoluble salts by precipitation material requirements: one solution contains the positive ions and the other contains the negative ions of the insoluble salts
other uses of precipitation used as a method to clean the water(remove harmful substances that dissolved in the water) make coloured pigments for paint make films(胶⽚) for photography(photographic film) finding concentration by titration find a solution of an alkali of a known concentration-as a standard solution method 1:
method 2:
