1. Dr. S. M. Condren Chapter 1 Chemistry and Measurement

2. Dr. S. M. Condren Chemistry What is it? Why do we study it?

3. Dr. S. M. Condren Physical States solid –fixed volume and shape liquid –fixed volume –shape of container, horizontal top surface gas –takes shape and volume of container liquid crystal –some characteristics of solid and some of liquid states

4. Dr. S. M. Condren Modern Chemistry: A Brief Glimpse

5. Dr. S. M. Condren “Exploring the Nanoworld” To order a kit (Special introductory price, $24 shipped to US addresses) contact the Institute for Chemical Education

6. Dr. S. M. Condren Air Bags: How Do They Work? http://whyfiles.news.wisc.edu/032air_bag/how_work.html

7. Dr. S. M. Condren Science and the Ozone Layer For more information about the Ozone Layer: Ozone Depletion –http://www.epa.gov/ozone/ Thickness of ozone layer –http://jwocky.gsfc.nasa.gov/teacher/ozone_overhead.html Memphis: +35 latitude -90 longitude

8. Dr. S. M. Condren Matter has mass mass vs. weight occupies space

9. Dr. S. M. Condren Scientific Method Experiment Results Hypothesis –further experiments –refine the hypothesis Theory –experiments to test the theory –refine the theory

10. Dr. S. M. Condren Law of Conservation of Mass In an ordinary chemical reaction matter is neither created nor destroyed. The sum of the masses of the reactants equals the sum of the masses of the products.

11. Dr. S. M. Condren Properties of Matter Extensive Property depends on specific sample under investigation examples: –mass and volume Intensive Property identical in all samples of the substance examples: –color, density, melting point, etc.

12. Dr. S. M. Condren Physical Property one that can be observed without changing the substances present in the sample changes in physical properties of substances

13. Dr. S. M. Condren Chemical Property the tendency to react and form new substances

14. Dr. S. M. Condren Chemical Reaction reactants undergo chemical change to produce products sucrose ---> carbon + water reactant products

15. Dr. S. M. Condren Chemical Reaction Reactions are indicated by: evolution of a gas change of color formation of a precipitate

16. Dr. S. M. Condren Law of Definite Proportions All samples of the same pure substance always contain the same elements in the same proportions by weight

17. Dr. S. M. Condren Pure Substances Elements Compounds

18. Dr. S. M. Condren Mixtures Heterogeneous uneven texture Homogeneous (Solution) sample uniform throughout

19. Dr. S. M. Condren

20. Separation of Mixtures filtration distillation chromatography

21. Dr. S. M. Condren Filtration separate solids by differences in melting points separate solids by differences in solubility (fractional crystallization) mechanical separation such as in Fig. 1.11 page 13.

22. Dr. S. M. Condren Distillation separation by differences in boiling point (fractional distillation) –distillate –distillation fractionating column - part of apparatus where separation occurs

23. Dr. S. M. Condren

24. Chromatography liquid-column paper thin-layer (TLC) gas HPLC electrophoresis (DNA mapping)

25. Dr. S. M. Condren Column Chromatography

26. Dr. S. M. Condren Paper Chromatography of Inks

27. Dr. S. M. Condren

28. Uncertainty in Measurements Accuracy closeness to true value vs Precision reproducibility

29. Dr. S. M. Condren Accurate and/or Precise?

30. Dr. S. M. Condren Accurate and/or Precise?

31. Dr. S. M. Condren Significant Figures Rules for determining which digits are significant: All non-zero numbers are significant Zeros between non-zero numbers are significant Zeros to the right of the non-zero number and to the right of the decimal point are significant Zeros before non-zero numbers are not significant

32. Dr. S. M. Condren Significant Figures Examples: Railroad Track Scale 70,000,000 g + 500,000 g 7.00 x 10 7 g (scientific notation) 7.00 E 7 g (engineering notation) 3 significant figures

33. Dr. S. M. Condren Significant Figures Examples: Regular Lab Balance 1,000 g + 0.1 g 1.0000 x 10 3 g 5 sig. fig. 400 g + 0.01 g 4.0000 x 10 2 g 5 sig. fig. 100 + 0.001 g 1.00000 x 10 2 g 6 sig.fig.

34. Dr. S. M. Condren Rules for Mathematics Multiplication and Division For multiplication and division, the number of significant figures used in the answer is the number in the value with the fewest significant figures. 2 sig.fig.;3 sig. fig. => 2 sig. fig. 4 sig. fig.; = 2.0 x 10 2 (2075)*(14) ---------------- (144)

35. Dr. S. M. Condren Rules for Mathematics Addition and Subtraction For addition and subtraction, the number of significant figures used in the answer is determined by the piece of data with the fewest number decimal places. 4.371 302.5 -------- 306.8

36. Dr. S. M. Condren Rules for Mathematics Addition and Subtraction For addition and subtraction, the number of significant figures used in the answer is determined by the piece of data with the fewest number decimal places. 4.371 302.5 -------- 306.8

37. Dr. S. M. Condren Rules for Mathematics Addition and Subtraction For addition and subtraction, the number of significant figures used in the answer is determined by the piece of data with the fewest number decimal places. 4.371 (I truncate extra data) 302.5 -------- 306.8

38. Dr. S. M. Condren Exact Numbers conversion factors should never limit the number of significant figures reported in answer 12 inches = 1 foot

39. Dr. S. M. Condren Round Off Chemistry is an inexact science all physical measurements have some error thus, there is some inexactness in the last digit of any number use what ever round-off procedure you choose reasonably close answers accepted

40. Dr. S. M. Condren Measurement and Units length - meter volume - liter mass - gram

41. Dr. S. M. Condren Important Metric Unit Prefixes deci -- 1/10* centi -- 1/100* milli -- 1/1000* nano -- 1/1,000,000,000 kilo -- 1000*

42. Dr. S. M. Condren Liter 1 liter = 1 decimeter 3 by definition where 1 decimeter = 10 centimeters therefore 1 liter = (10 centimeters) 3 or 1 liter =1000 cm 3 =1000 mL

43. Dr. S. M. Condren Millimeter 1 millimeter = 1/1000 meter 1000 millimeter = 1 meter 1000 mm = 1 m

44. Dr. S. M. Condren Nanometer 1 nanometer = 1/1,000,000,000 meter 1,000,000,000 nanometer = 1 meter 1,000,000,000 nm = 1 m

45. Dr. S. M. Condren Liter 1 liter = 1 decimeter 3 1 liter = 1000 milliliters 1 L = 1000 mL 1 mL = 0.001 L

46. Dr. S. M. Condren Milligram 1 milligram = 1/1000 gram 1 mg = 0.001 g

47. Dr. S. M. Condren Kilogram 1 kilogram = 1000 gram 1 g = 0.001 kg 1 mg = 0.000001 kg 1 kg = 1,000,000 mg

48. Dr. S. M. Condren Conversion of Units 1 in = 2.54 cm

49. Dr. S. M. Condren Temperature Scales: Fahrenheit Rankin –absolute scale using Fahrenheit size degree Celsius Kelvin –absolute scale using Celsius size degree

50. Dr. S. M. Condren

51. Comparison of Temperature Scales

52. Dr. S. M. Condren Temperature Relationships C = 100/180 * (F - 32) F = (180/100)*C + 32 K = C + 273.15 - 40 o F = - 40 o C

53. Dr. S. M. Condren If the temperature of the room goes from 20 degrees C to 40 degrees C, the ambient thermal energy –doubles –is halved –increases by less than 10%

54. Dr. S. M. Condren Density Mass per unit of volume Mass equals volume times density Volume equals mass divided by density

55. Dr. S. M. Condren Problem Solving by Factor Label Method state question in mathematical form set equal to piece of data specific to the problem use conversion factors to convert units of data specific to problem to units sought in answer

56. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles?

57. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? state question in mathematical form #km

58. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? set equal to piece of data specific to the problem #km = 0.200 miles

59. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? use conversion factors to convert units of data specific to problem to units sought in answer #km = (0.200 miles) * (5280 ft/mile)

60. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? cancel units #km = (0.200 miles) * (5280 ft/mile)

61. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? add another conversion factor #km = (0.200)*(5280 ft) *(12 in/ft)

62. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? cancel units #km = (0.200)*(5280 ft) *(12 in/ft)

63. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? #km = (0.200)*(5280)*(12 in)

64. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? add still another conversion factor #km = (0.200)*(5280)*(12 in) *(2.54 cm/in)

65. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? cancel units #km = (0.200)*(5280)*(12 in) *(2.54 cm/in)

66. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? #km = (0.200)*(5280)*(12)*(2.54 cm)

67. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? add still another conversion factor #km = (0.200)*(5280)*(12)*(2.54 cm) *(1 m/100 cm)

68. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? cancel units #km = (0.200)*(5280)*(12)*(2.54 cm) *(1 m/100 cm)

69. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? #km = (0.200)*(5280)*(12)*(2.54) *(1 m/100)

70. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? add still another conversion factor #km = (0.200)*(5280)*(12)*(2.54) *(1 m/100)*(1 km/1000 m)

71. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? cancel units #km = (0.200)*(5280)*(12)*(2.54) *(1 m/100)*(1 km/1000 m)

72. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? #km = (0.200)*(5280)*(12)*(2.54) *(1/100)*(1 km/1000)

73. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? solve mathematics #km = (0.200)*(5280)*(12)*(2.54) *(1/100)*(1 km/1000) = 0.322 km 3 sig. fig.

74. Dr. S. M. Condren Example How many kilometers are there in 0.200 miles? solve mathematics #km = (0.200)*(5280)*(12)*(2.54) *(1/100)*(1 km/1000) = 0.322 km 3 sig. fig.exact numbers