S2 Chemistry

1. S2 Chemistry Introduction to Chemistry

2. Introduction to Chemistry • 1.1 Reaction Rates • 1.2 Chemical Formula (elements) • 1.3 Chemical Formula (compounds)

3. 1.1 Reaction Rates • Learning Intentions • To learn how to speed up a chemical reaction

4. Success Criteria • I can list the 4 methods a reaction can be made faster. • I can describe the effect of a catalyst and an enzyme on a reaction • I can do experiments to show how a reaction’s speed can be increased. • I can evaluate and explain graphs showing speeds of reactions. • I can explain everyday reactions and how to speed them up.

5. Particle Size Apparatus • 0.5M hydrochloric acid • chalk lumps • chalk powder • 2 boiling tubes • test tube rack

6. Particle Size Method • Two boiling tubes were ¼ filled with 0.5M hydrochloric acid. • 4 lumps of chalk were put into one boiling tube • A similar quantity of chalk powder was put into the other boiling tube • Record your results

7. Particle Size Results • Decreasing the particle size (making the bits smaller) increases the rate of reaction.

8. Temperature Apparatus • glucose powder • Benedict’s solution • Metal beaker • Bunsen and bench mat • Tripod and gauze

9. Temperature Method • Half fill the metal beaker with water. Heat it with a blue flame until it is boiling then switch off the bunsen. • ¼ fill two test tubes with water. Put a spatula of glucose into each test tube. • Put 10 drops of Benedicts into each test tube • Place one of the test tubes into the hot water • Record your results.

10. Temperature Results • Increasing the temperature increased the rate of the reaction.

11. Concentration Method

12. Concentration Results

13. Summary • To speed up a chemical reaction you could - • Increase temperature • Increase concentration • Decrease particle size

14. Catalysts • A catalyst is a substance which increases the speed of a chemical reaction without itself being changed.

15. Enzymes • An enzyme is a biological catalyst

16. Enzymes • An enzyme is a biological catalyst • Liver contains an enzyme which speeds up certain chemical reactions.

17. We are learning to write element formula

18. 1.2 Chemical Formula (elements) • Learning Intention • We are learning to write element formula

19. Success Criteria • I can write formula for elements

20. Chemical Formula (elements) • All elements are given a name and a symbol • eg name hydrogen symbol H

21. Chemical Formula (elements) • Some elements have symbols that contain two or more letters • eg name magnesium symbol Mg

22. Chemical Formula (elements) • Some elements have symbols that contain two or more letters • eg name magnesium symbol Mg The first letter only must be a capital letter

23. 1.3 Chemical Formula (compounds) • Leanning Intention • We are learning to write chemical formula

24. Success Criteria • I can write chemical formula for compounds containing the prefixes mono, di, tri, tetra • I can write chemical formula for compounds with 2 elements • I can write chemical formula for compounds with more than 2 elements • I can write chemical formula for compounds containing roman numerals

25. Naming Compounds • A compound is formed when 2 or more different elements chemically join together.

26. Naming Compounds • -ide only two elements forming the compound • -ate two elements plus oxygen • -ite two elements plus oxygen

27. Naming Compounds

28. Naming Compounds

29. Valency or Combining Power • The valency or combining power is the number of connections an atom can have with another atom.

30. Linking Atoms

31. Using the Valency • If we know the valencies of the atoms combining then we can work out the formula of the compound they form. • Eg water

32. Using the Valency • Symbol H O

33. Using the Valency • Symbol H O • Valency 1 2

34. Using the Valency • Symbol H O • Valency 1 2 H O

35. Using the Valency • Symbol H O • Valency 1 2 H O H

36. Using the Valency • Symbol H O • Valency 1 2 H O H

37. Using the Valency • Symbol H O • Valency 1 2 H2O H O H No arms can be left unattached

38. Example – carbon hydride • Symbol C H

39. Using the Valency • Symbol C H • Valency 4 1

40. Using the Valency • Symbol C H • Valency 4 1 C H

41. Using the Valency • Symbol C H • Valency 4 1 H CH4 methane C H H H

42. Writing Formula • Calcium oxide • Magnesium sulphide • Calcium carbide • Aluminium phosphide • Calcium bromide

43. Writing Formula • Calcium oxide CaO • Magnesium sulphide MgS • Calcium carbide Ca2C • Aluminium phosphide AlP • Calcium bromide CaBr2

44. Writing Formula • In certain compounds the name tell you the formula • mono = 1 • di = 2 • tri = 3 • Tetra = 4 Eg nitrogen dioxide = NO2

45. Writing Formula • Dinitrogen tetraoxide • Hydrogen oxide • Carbon hydride • Nitrogen fluoride • Magnesium carbide • Potassium nitride

46. Writing Formula • Dinitrogen tetraoxide N2O4 • Hydrogen oxide H2O • Carbon hydride CH4 • Nitrogen fluoride NF3 • Magnesium carbide Mg2C • Potassium nitride K3N

47. Formula with groups • Groups of atoms can be given a valency as well • Eg the sulphate ion has a valency of 2 SO4

48. Formula with groups nitrate NO3 phosphate PO4 hydroxide OH

49. Formula Roman Numerals Roman numerals in a formula give the valency of the transition metal Eg iron (II) oxide

50. Formula Roman Numerals Roman numerals in a formula give the valency of the transition metal Eg iron (II) oxide O Fe