1. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 1 Foundations of Chemistry A quick review!

2. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 2 Steps in the Scientific Method 1.Observations  quantitative  qualitative 2.Formulating hypotheses  possible explanation for the observation 3.Performing experiments  gathering new information to decide whether the hypothesis is valid whether the hypothesis is valid

3. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 3 Outcomes Over the Long-Term Theory (Model)  A set of tested hypotheses that give an overall explanation of some natural phenomenon. overall explanation of some natural phenomenon. Natural Law  The same observation applies to many different systems different systems  Example - Law of Conservation of Mass

4. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 4 The Fundamental Steps of the Scientific Method

5. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 5 The Various Parts of the Scientific Method

6. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 6 Law v. Theory A law summarizes what happens; A theory (model) is an attempt to explain why it happens.

7. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 7 Nature of Measurement Measurement - quantitative observation consisting of 2 parts Part 1 - number Part 2 - scale (unit) Part 2 - scale (unit)Examples: 20 grams 6.63    Joule seconds

8. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 8 International System (le Système International) Based on metric system and units derived from metric system.

9. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 9 The Fundamental SI Units

10. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 10 Measurement of Volume

11. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 11 Common Types of Laboratory Equipment Used to Measure Liquid Volume

12. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 12 Measurement of Volume Using a Buret The volume is read at the bottom of the liquid curve (called the meniscus).

13. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 13 Uncertainty in Measurement A digit that must be estimated is called uncertain. A measurement always has some degree of uncertainty.

14. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 14 Precision and Accuracy Accuracy refers to the agreement of a particular value with the true value. Precision refers to the degree of agreement among several elements of the same quantity.

15. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 15 The Difference between Precision and Accuracy

16. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 16 Types of Error Random Error (Indeterminate Error) - measurement has an equal probability of being high or low. Systematic Error (Determinate Error) - Occurs in the same direction each time (high or low), often resulting from poor technique.

17. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 17 Rules for Counting Significant Figures - Overview 1.Nonzero integers 2.Zeros  leading zeros  captive zeros  trailing zeros 3.Exact numbers

18. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 18 Rules for Counting Significant Figures - Details Nonzero integers always count as significant figures. 3456 has 4 sig figs.

19. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 19 Rules for Counting Significant Figures - DetailsZeros  Leading zeros do not count as significant figures. 0.0486 has 3 sig figs.

20. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 20 Rules for Counting Significant Figures - DetailsZeros  Captive zeros always count as  Captive zeros always count as significant figures. 16.07 has 4 sig figs.

21. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 21 Rules for Counting Significant Figures - DetailsZeros  Trailing zeros are significant only  Trailing zeros are significant only if the number contains a decimal point. 9.300 has 4 sig figs.

22. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 22 Rules for Counting Significant Figures - Details Exact numbers have an infinite number of significant figures. 1 inch = 2.54 cm, exactly

23. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 23 Rules for Significant Figures in Mathematical Operations Multiplication and Division: # sig figs in the result equals the number in the least precise measurement used in the calculation. 6.38  2.0 = 12.76  13 (2 sig figs)

24. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 24 Rules for Significant Figures in Mathematical Operations Addition and Subtraction: # sig figs in the result equals the number of decimal places in the least precise measurement. 6.8 + 11.934 = 22.4896  22.5 (3 sig figs)

25. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 25 Dimensional Analysis Proper use of “unit factors” leads to proper units in your answer.

26. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 26 Temperature Celsius scale =  C Kelvin scale = K Fahrenheit scale =  F

27. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 27 The Three Major Temperature Scales

28. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 28 Normal Body Temperature on the Fahrenheit, Celsius, and Kelvin Scales

29. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 29 Temperature

30. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 30 Density Density is the mass of substance per unit volume of the substance:

31. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 31 Matter: Anything occupying space and having mass.

32. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 32 Classification of Matter Three States of Matter: Solid: rigid - fixed volume and shape Liquid: definite volume but assumes the shape of its container Gas: no fixed volume or shape - assumes the shape of its container

33. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 33 Types of Mixtures Mixtures have variable composition. A homogeneous mixture is a solution (for example, vinegar) A heterogeneous mixture is, to the naked eye, clearly not uniform (for example, a bottle of ranch dressing)

34. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 34 Pure Substances Can be isolated by separation methods:  Chromatography  Filtration  Distillation

35. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 35 Simple Laboratory Distillation Apparatus

36. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 36 Element: A substance that cannot be decomposed into simpler substances by chemical means. Compound: A substance with a constant composition that can be broken down into elements by chemical processes.

37. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 37 The Organization of Matter

38. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 38 The Early History of Chemistry Before 16th Century Alchemy: Attempts (scientific or otherwise) to change cheap metals into gold 17th Century Robert Boyle: First “chemist” to perform quantitative experiments 18th Century George Stahl: Phlogiston flows out of a burning material. Joseph Priestley: Discovers oxygen gas, “dephlogisticated air.”

39. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 39 Law of Conservation of Mass Discovered by Antoine Lavoisier Mass is neither created nor destroyed Combustion involves oxygen, not phlogiston

40. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 40 Other Fundamental Chemical Laws A given compound always contains exactly the same proportion of elements by mass. Carbon tetrachloride is always 1 atom carbon per 4 atoms chlorine. Law of Definite Proportion

41. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 41 Other Fundamental Chemical Laws When two elements form a series of compounds, the ratios of the masses of the second element that combine with 1 gram of the first element can always be reduced to small whole numbers. The ratio of the masses of oxygen in H 2 O and H 2 O 2 will be a small whole number (“2”). Law of Multiple Proportions

42. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 42 Dalton’s Atomic Theory (1808) Each element is made up of tiny particles called atoms. The atoms of a given element are identical; the atoms of different elements are different in some fundamental way or ways.

43. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 43 Dalton’s Atomic Theory (continued) Chemical compounds are formed when atoms combine with each other. A given compound always has the same relative numbers and types of atoms. Chemical reactions involve reorganization of the atoms - changes in the way they are bound together. The atoms themselves are not changed in a chemical reaction.

44. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 44 Representation of some of Gay-Lussac’s Experimental Results on Combining Gas Volumes

45. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 45 Representation of Combining Gases at the Molecular Level

46. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 46 Avogadro’s Hypothesis (1811) 5 liters of oxygen 5 liters of nitrogen Same number of particles! At the same temperature and pressure, equal volumes of different gases contain the same number of particles.

47. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 47 Early Experiments to Characterize the Atom J. J. Thomson - postulated the existence of electrons using cathode ray tubes. Ernest Rutherford - explained the nuclear atom, containing a dense nucleus with electrons traveling around the nucleus at a large distance.

48. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 48 Deflection of Cathode Rays by an Applied Electric Field

49. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 49 The Plum Pudding Model of the Atom

50. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 50 Diagram of the Millikan Apparatus

51. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 51 Rutherford’s Experiment on  particle Bombardment of Metal Foil

52. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 52 Expected and Actual Results of Rutherford’s Experiment

53. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 53 The Modern View of Atomic Structure electrons protons: found in the nucleus, they have a positive charge equal in magnitude to the electron’s negative charge. neutrons: found in the nucleus, virtually same mass as a proton but no charge. The atom contains:

54. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 54 The Mass and Change of the Electron, Proton, and Neutron

55. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 55 Nuclear Atom Viewed in Cross Section

56. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 56 The Chemists’ Shorthand: Atomic Symbols K  Element Symbol 39 19 Mass number  Atomic number 

57. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 57 Two Isotopes of Sodium

58. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 58 Chemical Bonds The forces that hold atoms together in compounds. Covalent bonds result from atoms sharing electrons. Molecule: a collection of covalently-bonded atoms.

59. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 59 Two Isotopes of Sodium

60. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 60 The Structural Formula for Methane

61. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 61 Sodium Chloride

62. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 62 The Chemists’ Shorthand: Formulas Chemical Formula: Symbols = types of atoms Subscripts = relative numbers of atoms CO 2 Structural Formula: Individual bonds are shown by lines. O=C=OO=C=O

63. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 63 Ions Cation: A positive ion Mg 2+, NH 4 + Anion: A negative ion Cl , SO 4 2  Ionic Bonding: Force of attraction between oppositely charged ions.

64. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 64 Periodic Table Elements classified by:  properties  atomic number Groups (vertical) 1A = alkali metals 2A = alkaline earth metals 7A = halogens 8A = noble gases Periods (horizontal)

65. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 65 The Periodic Table

66. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 66 Naming Compounds 1. Cation first, then anion 2. Monatomic cation = name of the element Ca 2+ = calcium ion 3. Monatomic anion = root + -ide Cl  = chloride CaCl 2 = calcium chloride Binary Ionic Compounds:

67. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 67 Naming Compounds (continued)  metal forms more than one cation  use Roman numeral in name PbCl 2 Pb 2+ is cation PbCl 2 = lead (II) chloride Binary Ionic Compounds (Type II):

68. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 68 Common Cations and Anions

69. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 69 Naming Compounds (continued)  Compounds between two nonmetals  First element in the formula is named first.  Second element is named as if it were an anion.  Use prefixes  Never use mono- P 2 O 5 = diphosphorus pentoxide Binary compounds (Type III):

70. Copyright©2000 by Houghton Mifflin Company. All rights reserved. 70 Flowchart for Naming Binary Compounds