rack; 2 boiling tubes; balance; spatula; stirring rod; water; universal indicator white tile Digital Equations to solution; aluminium universal indicator paper; pH balance presentation oxide powder; calcium colour chart; dilute hydrochloric oxide powder: small acid; calcium hydroxide powder spatula graph paper CC9e Alkalis and C3.14 Explain an acid-alkali 1) In pairs using paper or Students carry out a practical in Demonstrate the neutralisation neutralisation as a reaction in mini-whiteboards, which they produce sodium technique of titration which hydrogen ions (H+) students balance chloride crystals. Titration is and the use of the from the acid react with equations supplied on used to neutralise dilute sodium volumetric pipette and hydroxide ions (OH–) from the board, then peer hydroxide solution with dilute filler. the alkali. assess their answers with hydrochloric acid, and then Equipment: eye C3.16 Explain why, if soluble salts another pair. repeated without the indicator. protection; 100 cm3 are prepared from an acid Students then use beaker; 250 cm3 and a soluble reactant: 2) Ask the students to crystallisation to produce beaker; 250 cm3 a titration must be used list all the apparatus they sodium chloride from the conical flask; 25 cm3 b the acid and the soluble can think of that solution formed. volumetric pipette and reactant are then mixed in measures volume, then filler; burette; filter the correct proportions rate each one according The end-point should occur at funnel; white tile; 0.5 c the solution remaining, to its accuracy and about 25.0 cm3 mol dm–3 hydrochloric after reaction, is only salt capacity. (phenolphthalein indicator acid; 0.5 mol dm–3 and water changes from pink to sodium hydroxide C3.18 Describe how to carry out an colourless), with about 0.7 g of solution; acid-alkali titration, using sodium chloride produced in phenolphthalein burette, pipette and a total. indicator. suitable indicator, to prepare a pure, dry salt. Equipment: eye protection; Digital Apparatus for 100 cm3 beaker; 250 cm3 titration presentation beaker; 100 cm3 conical flask; 250 cm3 conical flask
rack; 2 boiling tubes; water; universal indicator solution; aluminium oxide powder; calcium oxide powder: small spatula balance; spatula; stirring rod; white tile universal indicator paper; pH colour chart; dilute hydrochloric acid; calcium hydroxide powder graph paper Digital Equations to balance presentation CC9e Alkalis and neutralisation C3.14 C3.16 C3.18 Explain an acid-alkali neutralisation as a reaction in which hydrogen ions (H+) from the acid react with hydroxide ions (OH–) from the alkali. Explain why, if soluble salts are prepared from an acid and a soluble reactant: a titration must be used b the acid and the soluble reactant are then mixed in the correct proportions c the solution remaining, after reaction, is only salt and water Describe how to carry out an acid-alkali titration, using burette, pipette and a suitable indicator, to prepare a pure, dry salt. 1) In pairs using paper or mini-whiteboards, students balance equations supplied on the board, then peer assess their answers with another pair. 2) Ask the students to list all the apparatus they can think of that measures volume, then rate each one according to its accuracy and capacity. Students carry out a practical in which they produce sodium chloride crystals. Titration is used to neutralise dilute sodium hydroxide solution with dilute hydrochloric acid, and then repeated without the indicator. Students then use crystallisation to produce sodium chloride from the solution formed. The end-point should occur at about 25.0 cm3 (phenolphthalein indicator changes from pink to colourless), with about 0.7 g of sodium chloride produced in total. Equipment: eye protection; 100 cm3 beaker; 250 cm3 beaker; 100 cm3 conical flask; 250 cm3 conical flask Demonstrate the technique of titration and the use of the volumetric pipette and filler. Equipment: eye protection; 100 cm3 beaker; 250 cm3 beaker; 250 cm3 conical flask; 25 cm3 volumetric pipette and filler; burette; filter funnel; white tile; 0.5 mol dm–3 hydrochloric acid; 0.5 mol dm–3 sodium hydroxide solution; phenolphthalein indicator. Digital Apparatus for titration presentation