cm3 0.5 mol dm-3 solution), potassium iodide solution (40 cm3 0.5 mol dm-3 solution) Digital Moles presentation Demonstrate the CC9a Acids, C3.1 Recall that acids in solution Ask students to write Students test a series of electrolysis of a number alkalis and are sources of hydrogen ions down three or four facts indicators including: litmus, indicators and alkalis in solution are they can remember methyl orange and of acid solutions: sulfuric sources of hydroxide ions about about: acids, phenolphthalein. by adding an acid, nitric acid and C3.2 Recall that a neutral solution alkalis and neutral alkali to and acid 1 cm3 at a hydrochloric acid collect has a pH of 7 and that acidic solutions. They then time while measuring the pH the gas at the negative solutions have lower pH compare their lists in and noting when any colour electrode and test for values and alkaline solutions groups. changes occurs. hydrogen. higher pH values C3.3 Recall the effect of acids and Students are aware of colour Link to the idea that alkalis on indicators, changes for range of indicators acids always contain including litmus, methyl and note that the colour change hydrogen ions orange and phenolphthalein is not always at pH 7 C3.4 Recall that the higher the Digital TBC concentration of hydrogen Equipment: TBC ions in an acidic solution, the lower the pH; and the higher the concentration of hydroxide ions in an alkaline solution, the higher the pH
cm3 0.5 mol dm-3 solution), potassium iodide solution (40 cm3 0.5 mol dm-3 solution) Digital Moles presentation CC9a Acids, alkalis and indicators C3.1 C3.2 C3.3 C3.4 Recall that acids in solution are sources of hydrogen ions and alkalis in solution are sources of hydroxide ions Recall that a neutral solution has a pH of 7 and that acidic solutions have lower pH values and alkaline solutions higher pH values Recall the effect of acids and alkalis on indicators, including litmus, methyl orange and phenolphthalein Recall that the higher the concentration of hydrogen ions in an acidic solution, the lower the pH; and the higher the concentration of hydroxide ions in an alkaline solution, the higher the pH Ask students to write down three or four facts they can remember about about: acids, alkalis and neutral solutions. They then compare their lists in groups. Students test a series of indicators including: litmus, methyl orange and phenolphthalein. by adding an alkali to and acid 1 cm3 at a time while measuring the pH and noting when any colour changes occurs. Students are aware of colour changes for range of indicators and note that the colour change is not always at pH 7 Equipment: TBC Demonstrate the electrolysis of a number of acid solutions: sulfuric acid, nitric acid and hydrochloric acid collect the gas at the negative electrode and test for hydrogen. Link to the idea that acids always contain hydrogen ions Digital TBC
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