Properties of substances

1. Properties of substances SG Chemistry, Topic 7

2. Conductivity of elements and compounds Standard Grade Chemistry Topic 7

4. Gold Sodium Carbon Hydrogen • What do the above substances have in common? • Elements • Which of them conduct electricity? Lead Silicon Iodine Bromine Mercury Sulphur Potassium Phosphorus

5. Gold Sodium Carbon Hydrogen • What do the above substances have in common? • Elements • Which of them conduct electricity? • Metal elements and carbon (graphite) • Does it make a difference what state the elements are in? • No Lead Silicon Iodine Bromine Mercury Sulphur Potassium Phosphorus

6. Graphite and diamond

7. Write a rule which summarises which elements can conduct electricity. • All metal elements can conduct electricity (whether solid or liquid); non-metal elements do not conduct electricity in any state, with the exception of carbon (graphite).

8. True or false • All solid elements conduct electricity. • All liquid elements conduct electricity. • All metal elements conduct electricity. • No non-metal element conducts electricity. • Solid oxygen conducts electricity. • Liquid oxygen conducts electricity. • Solid calcium conducts electricity. • Liquid calcium conducts electricity. • Solid carbon conducts electricity.

9. True or false • All solid elements conduct electricity. • All liquid elements conduct electricity. • All metal elements conduct electricity. • No non-metal element conducts electricity. • Solid oxygen conducts electricity. • Liquid oxygen conducts electricity. • Solid calcium conducts electricity. • Liquid calcium conducts electricity. • Solid carbon conducts electricity.

11. Practical – conductivity of compounds • If you were to investigate whether a compound can conduct electricity or not, what equipment would you need? • Power pack / battery • Wires • Bulb

12. COMPOUND

13. COMPOUND

14. Practical – conductivity of compounds • Which compounds would you chose to investigate?

15. Results • Do compounds of metals/non-metals conduct electricity when solid? • No • Do compounds of metals/non-metals conduct electricity when liquid? • Yes • Do compounds of metals/non-metals conduct electricity when dissolved? • Yes

16. Results • Do compounds of non-metals/non-metals conduct electricity when solid? • No • Do compounds of non-metals/non-metals conduct electricity when liquid? • No • Do compounds of non-metals/non-metals conduct electricity when dissolved? • No

17. Do they conduct electricity? • Solid sodium chloride (salt) • Solid glucose (C6H12O6) • Liquid potassium iodide • Solid methane • Dissolved lithium nitrate • CaO(s) • Al(OH)3(l) • CsCl(aq) • H2O2(l) • C12H22O11(aq)

18. Do they conduct electricity? • Solid sodium chloride (salt) • Solid glucose (C6H12O6) • Liquid potassium iodide • Solid methane • Dissolved lithium nitrate • CaO(s) • Al(OH)3(l) • CsCl(aq) • H2O2(l) • C12H22O11(aq)

20. Ions Standard Grade Chemistry Topic 7

22. Ion migration Standard Grade Chemistry Topic 7

24. Thought experiment

25. Thought experiment: NaCl(aq)

26. Thought experiment: C6H12O6(aq)

27. Why the difference? • Types of elements present? • Types of particle each is made up of?

31. Electrolysis Standard Grade Chemistry Topic 7

38. Theory of dissolving / melting + + - - + - + + - - + - + - + - + - +

39. + - + - - - - + + - + + - - + + - - + + Electrolysis + Copper - Chloride Why must a d.c. power supply be used? What happens to the mass of each electrode?

40. Chemistry of electrolysis

44. Why can ionic compounds conduct electricity? Standard Grade Chemistry Topic 7

47. Conduction and molecules Solid Liquid or solution Particles can’t move freely Particles can move freely Does not conduct – no charged particles Does not conduct – no charged particles

48. Conduction and ions + + - - + - + + - - + - + - + - + - + Solid Liquid or solution Particles can’t move freely Particles can move freely Does not conduct – ions can’t move freely Conducts – ions can move freely

49. The rule • To conduct, charged particles must be able to move freely. • In compounds, the charged particles are ions. • The compound must be a liquid (melt) or dissolved to conduct.