Chapter 1

1. Chapter 1 Chemistry and Measurement

2. Chemistry What is it? Why do we study it?

3. 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. Modern Chemistry: A Brief Glimpse

5. Air Bags: How Do They Work? http://whyfiles.news.wisc.edu/032air_bag/how_work.html

6. 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

7. Matter has mass mass vs. weight occupies space

8. Scientific Method Experiment Results Hypothesis further experiments refine the hypothesis Theory experiments to test the theory refine the theory

9. 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.

10. 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.

11. Physical Property one that can be observed without changing the substances present in the sample changes in physical properties of substances

12. Chemical Property the tendency to react and form new substances

13. Chemical Reaction reactants undergo chemical change to produce products sucrose ---> carbon + water reactantproducts

14. Chemical Reaction Reactions are indicated by: evolution of a gas change of color formation of a precipitate

15. Law of Definite Proportions All samples of the same pure substance always contain the same elements in the same proportions by weight

16. Pure Substances Elements Compounds

17. Mixtures Heterogeneous uneven texture Homogeneous (Solution) sample uniform throughout

19. Separation of Mixtures filtration distillation chromatography

20. 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.

21. Distillation separation by differences in boiling point (fractional distillation) distillate distillation fractionating column - part of apparatus where separation occurs

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

24. Column Chromatography

25. Paper Chromatography of Inks

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

28. Accurate and/or Precise?

29. Accurate and/or Precise?

30. 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

31. Significant FiguresExamples: Railroad Track Scale 70,000,000 g + 500,000 g 7.00x 107 g (scientific notation) 7.00E7g (engineering notation) 3 significant figures

32. Significant FiguresExamples: Regular Lab Balance 1,000 g + 0.1 g 1.0000x 103 g 5 sig. fig. 400 g + 0.01 g 4.0000x 102 g 5 sig. fig. 100 + 0.001 g 1.00000x 102 g 6 sig.fig.

33. Rules for MathematicsMultiplication 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. (2075)*(14) ---------------- (144) = 2.0 x 102 4 sig. fig.; => 2 sig.fig.; 3 sig. fig. 2 sig. fig.

34. Rules for MathematicsAddition 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

35. Rules for MathematicsAddition 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. Rules for MathematicsAddition 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. Exact Numbers conversion factors should never limit the number of significant figures reported in answer 12 inches = 1 foot

38. 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

39. Measurement and Units length - meter volume - liter mass - gram

40. Important Metric Unit Prefixes deci -- 1/10* centi -- 1/100* milli -- 1/1000* nano -- 1/1,000,000,000 kilo -- 1000*

41. Liter 1 liter = 1 decimeter3 by definition where 1 decimeter = 10 centimeters therefore 1 liter = (10 centimeters)3 or 1 liter =1000 cm3 =1000 mL

42. Millimeter 1 millimeter = 1/1000 meter 1000 millimeter = 1 meter 1000 mm = 1 m

43. Nanometer 1 nanometer = 1/1,000,000,000 meter 1,000,000,000 nanometer = 1 meter 1,000,000,000 nm = 1 m

44. Liter 1 liter = 1 decimeter3 1 liter = 1000 milliliters 1 L = 1000 mL 1 mL = 0.001 L

45. Milligram 1 milligram = 1/1000 gram 1 mg = 0.001 g

46. Kilogram 1 kilogram = 1000 gram 1 g = 0.001 kg 1 mg = 0.000001 kg 1 kg = 1,000,000 mg

47. Conversion of Units 1 in = 2.54 cm

48. Temperature Scales: Fahrenheit Rankin absolute scale using Fahrenheit size degree Celsius Kelvin absolute scale using Celsius size degree

50. Comparison of Temperature Scales