a high melting points and Place the electrodes into magnetic model is boiling points, in terms of a spatula of solid sodium available, the ions can Students should find that forces between ions chloride crystals in a be separated to copper sulfate, potassium small glass beaker and represent melting and b whether or not they iodide and sodium chloride are show that the lamp does they can then move conduct electricity as solids, ionic compounds. not light up – so solid from one electrode to when molten and in aqueous Ethanol, sugar and water are sodium chloride does not another, so molten solution not ionic compounds. conduct electricity. ionic compounds do Remove the electrodes, conduct electricity. add about 40 cm3 Equipment each group needs: Emphasise that charged boiling tube with bung to fit, distilled or de-ionised particles that can move water to the beaker of 100 cm3 beaker, d.c. power are needed for a sodium chloride and stir supply, dropper pipette, eye substance to conduct to dissolve as much as protection, two graphite electricity. Ionic possible. Replace the electrodes, lamp in a holder, compounds always electrodes and the lamp leads and crocodile clips, contain ions, which are lights, showing that spatula, substances to test – charged particles. Show sodium chloride solution copper sulfate, ethanol, that the ions are held in does conduct electricity. potassium iodide, sodium fixed positions in the chloride, sugar and distilled or solid state so they Ask the students to de-ionised water cannot move from one explain these electrode to the other, observations and so solid ionic compounds do not Equipment d.c. power conduct electricity. supply, connecting leads and crocodile clips, two Equipment d.c. power graphite electrodes, lamp supply, lamp in a in a holder, 100 cm3 holder, two graphite glass beaker, glass rod, electrodes, connecting sodium chloride (salt) leads and crocodile crystals, distilled or clips, evaporating water, optional:
a high melting points and boiling points, in terms of forces between ions b whether or not they conduct electricity as solids, when molten and in aqueous solution Place the electrodes into a spatula of solid sodium chloride crystals in a small glass beaker and show that the lamp does not light up – so solid sodium chloride does not conduct electricity. Remove the electrodes, add about 40 cm3 distilled or de-ionised water to the beaker of sodium chloride and stir to dissolve as much as possible. Replace the electrodes and the lamp lights, showing that sodium chloride solution does conduct electricity. Ask the students to explain these observations Equipment d.c. power supply, connecting leads and crocodile clips, two graphite electrodes, lamp in a holder, 100 cm3 glass beaker, glass rod, sodium chloride (salt) crystals, distilled or water, optional: Students should find that copper sulfate, potassium iodide and sodium chloride are ionic compounds. Ethanol, sugar and water are not ionic compounds. Equipment each group needs: boiling tube with bung to fit, 100 cm3 beaker, d.c. power supply, dropper pipette, eye protection, two graphite electrodes, lamp in a holder, leads and crocodile clips, spatula, substances to test – copper sulfate, ethanol, potassium iodide, sodium chloride, sugar and distilled or de-ionised water magnetic model is available, the ions can be separated to represent melting and they can then move from one electrode to another, so molten ionic compounds do conduct electricity. Emphasise that charged particles that can move are needed for a substance to conduct electricity. Ionic compounds always contain ions, which are charged particles. Show that the ions are held in fixed positions in the solid state so they cannot move from one electrode to the other, and so solid ionic compounds do not conduct electricity. Equipment d.c. power supply, lamp in a holder, two graphite electrodes, connecting leads and crocodile clips, evaporating
GCSE-9-1-Science-Term-2-detailed-planning-document.docx