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PRACTICAL WORK SAFETY: WEAR LAB COAT and SAFETY GLASSES. If in doubt, ask the lecturer! Stations are already set up containing: burette, deionised water, ethanol, hexane, polythene rod + wool for rubbing (electrostatic charges), corks for hexane tubes. C6 14 Other materials: test tubes, powdered graphite, iodine, calcium chloride. Make appropriate tables for the results. PROCEDURES * Stations 1-3. Charge a polythene rod by rubbing it on a piece of wool; hold the rod about 1 cm from a jet of fluid issuing from a burette and note what happens: (1) water (2) ethanol (3) hexane Q1 C2H5OH What sort of particles does each contain? Q2 Are these particles polar? Q3 Explain the effect of the charged rod on each jet Q4 What might happen with a rod of opposite charge? (ask for a glass rod + cloth) Q5 Explain the behaviour of the liquids with the charged rod to the nature of the particles. Q6 Look up the boiling points and relative molecular masses of water, ethanol and hexane; compare their values in terms of polarity. *Test tubes 4-6. Observe and note the solubility, colour, etc., of one crystal of (a) calcium chloride, (b) powdered graphite and (c) iodine in test tubes (9 tubes) containing 4 cm depth each of: (4a,b,c) water (5a,b,c) ethanol (6a,b,c) hexane Q7 What sort of particles do calcium chloride, powdered graphite and iodine contain? Q8 What forces holds these particles together in the solid? Q9 Explain the relative solubility of each solid in each of the three liquids Q10 Try to explain the colour of iodine in different solvents. Make a brief plan of another experiment you could do to test your idea. * Test tube 7. Miscibility of water and hexane: Dispense into one test tube in order: (7) 2 cm water then 2 cm hexane, then one crystal of iodine; replace cork and gently mix Note your observations, replace in the rack. Q11 Which solvent do you think forms the upper layer? Explain!