1. 1 Introduction: Matter and Measurement Chapter 1

2. 2 The Study of Chemistry Chemistry is the study of the properties and behavior of matter. Matter – anything that occupies space and has mass. What is chemistry?

3. 3 Classification of Matter States of Matter

4. 4 Classification of Matter States of Matter Gas Liquid Solid

5. 5 Classification of Matter States of Matter ShapeVolume Gas Liquid Solid

6. 6 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquid Solid

7. 7 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquid Solid

8. 8 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquidindefinite Solid

9. 9 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquidindefinitedefinite Solid

10. 10 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquidindefinitedefinite Soliddefinite

11. 11 Classification of Matter States of Matter ShapeVolume Gasindefinite Liquidindefinitedefinite Soliddefinite

12. 12 Classification of Matter The basic difference between these states is the distance between the “bodies.” Gas – bodies are far apart and in rapid motion. Liquid – bodies closer together, but still able to move past each other. Solid – bodies are closer still and are now held in place in a definite arrangement.

13. 13 Classification of Matter

14. 14 Classification of Matter Mixture – combination of two or more substances in which each substance retains its own chemical identity. Homogeneous mixture – composition of this mixture is consistent throughout. Heterogeneous mixture – composition of this mixture varies throughout the mixture. Pure Substances and Mixtures

15. 15 Classification of Matter It is also possible for a homogeneous substance to be composed of a single substance – pure substance. Element – A substance that can not be separated into simpler substances by chemical means. Compound – A substance composed of two or more elements united chemically in definite proportions. Pure Substances and Mixtures

16. 16 Classification of Matter The smallest unit of an element is an atom. Atom – the smallest unit of an element that retains a substances chemical activity. Pure Substances and Mixtures

17. 17 Classification of Matter Mixtures can be separated by physical means. –Filtration. –Chromatography. –Distillation. Separation of Mixtures

18. 18 Classification of Matter Separation of Mixtures

19. 19 Classification of Matter There are 114 elements known. Each element is given a unique chemical symbol (one or two letters). –Carbon C, nitrogen N, titanium Ti. –Notice that the two letter symbols are always capital letter then lower case letter because: CO – carbon and oxygen. Co – element cobalt. Elements

20. 20 Classification of Matter Formed by combining elements. The proportions of elements in compounds are the same irrespective of how the compound was formed. Law of Constant Composition (or Law of Definite Proportions): –The composition of a pure compound is always the same, regardless of its source. Compounds

21. 21 Properties of Matter Physical Property (Change) – A property that can be measured without changing the identity of the substance. Example: melting point, boiling point, color, odor, density Physical changes do not result in a change of composition. Physical and Chemical Changes

22. 22 Properties of Matter Intensive properties – independent of sample size. Extensive properties - depends on the quantity of the sample. Physical and Chemical Changes

23. 23 Properties of Matter Chemical change (chemical reaction) – the transformation of a substance into a chemically different substance. –When pure hydrogen and pure oxygen react completely, they form pure water. Physical and Chemical Changes

24. 24 Scientific Method

25. 25 Scientific Method Hypothesis – tentative explanation based on a limited number of observations. Scientific law – A concise verbal or mathematical equation that summarizes a broad variety of observations and experiences. Theory – an explanation of the general principles of certain phenomena with considerable evidence or facts to support it.

26. 26 Units of Measurement There are two types of units: – –fundamental (or base) units; – –derived units. There are 7 base units in the SI system. Derived units are obtained from the 7 base SI units. SI Units

27. 27 Units of Measurement There are two types of units: – –fundamental (or base) units; – –derived units. There are 7 base units in the SI system. Derived units are obtained from the 7 base SI units. Example: SI Units

28. 28 SI Units Units of Measurement

29. 29 Units of Measurement SI Units

30. 30 Mass is the measure of the amount of material in an object. –This is not the same as weight which is dependant on gravity. Units of Measurement Mass

31. 31 Units of Measurement Temperature

32. 32 Units of Measurement Kelvin Scale Used in science. Same temperature increment as Celsius scale. Lowest temperature possible (absolute zero) is zero Kelvin. Absolute zero: 0 K = -273.15 o C. Celsius Scale Also used in science. Water freezes at 0 o C and boils at 100 o C. To convert: K = o C + 273.15. Fahrenheit Scale Not generally used in science. Water freezes at 32 o F and boils at 212 o F. Temperature

33. 33 Units of Measurement Converting between Celsius and Fahrenheit Temperature

34. 34 Units of Measurement The units for volume are given by (units of length) 3. – –i.e., SI unit for volume is 1 m 3. A more common volume unit is the liter (L) – –1 L = 1 dm 3 = 1000 cm 3 = 1000 mL. We usually use 1 mL = 1 cm 3. Volume

35. 35 Units of Measurement Density – mass per unit volume of an object. Density

36. 36 All scientific measures are subject to error. These errors are reflected in the number of figures reported for the measurement. These errors are also reflected in the observation that two successive measures of the same quantity are different. Uncertainty in Measurement

37. 37 Measurements that are close to the “correct” value are accurate. Measurements which are close to each other are precise. Measurements can be – –accurate and precise – –precise but inaccurate – –neither accurate nor precise Uncertainty in Measurement Precision and Accuracy

38. 38 Precision and Accuracy Uncertainty in Measurement

39. 39 Uncertainty in Measurement The number of digits reported in a measurement reflect the accuracy of the measurement and the precision of the measuring device. All the figures known with certainty plus one extra figure are called significant figures. In any calculation, the results are reported to the fewest significant figures (for multiplication and division) or fewest decimal places (addition and subtraction). Significant Figures

40. 40 Uncertainty in Measurement Non-zero numbers are always significant. Zeros between non-zero numbers are always significant. Zeros before the first non-zero digit are not significant. Zeros at the end of the number after a decimal place are significant. Zeros at the end of a number before a decimal place are ambiguous. For this course we will consider these to be significant. – –Example – so for this class, the number 10,300 has 5 significant figures. Significant Figures

41. 41 Uncertainty in Measurement Multiplication / DivisionMultiplication / Division –The result must have the same number of significant figures as the least accurately determined data Example: 12.512 (5 sig. fig.) 5.1 (2 sig. fig.) 12.512 x 5.1 = 64 Answer has only 2 significant figures Significant Figures

42. 42 Uncertainty in Measurement Addition / Subtraction.Addition / Subtraction. –The result must have the same number of digits to the right of the decimal point as the least accurately determined data. Example: 15.152 (5 sig. fig., 3 digits to the right), 1.76 (3 sig. fig., 2 digits to the right), 7.1 (2 sig. fig., 1 digit to the right). 15.152 + 1.76 + 7.1 = 24.0 24.0 (3 sig. fig., but only 1 digit to the right of the decimal point) Significant Figures

43. 43 Uncertainty in Measurement If the leftmost digit to be removed is less than 5, the preceding number is left unchanged. “Round down.” If the leftmost digit to be removed is 5 or greater, the preceding number is increased by 1. “Round up.” Rounding rules

44. 44 Dimensional Analysis In dimensional analysis always ask three questions: What data are we given? What quantity do we need? What conversion factors are available to take us from what we are given to what we need?

45. 45 Dimensional Analysis Method of calculation using a conversion factor.

46. 46 Dimensional Analysis Example: we want to convert the distance 8 in. to feet. (12in = 1 ft)

47. 47 Dimensional Analysis Example: we want to convert the distance 8 in. to feet. (12in = 1 ft)

48. 48 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm)

49. 49 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm) First we will need to determine the conversion factors Centimeter (cm)  Meter (m) Meter (m)  Nanometer (nm)

50. 50 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm) First we will need to determine the conversion factors Centimeter (cm)  Meter (m) Meter (m)  Nanometer (nm) Or 1 cm = 0.01 m 1 x 10 -9 m = 1 nm

51. 51 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm) 1 cm = 0.01 m 1 x 10 -9 m = 1 nm Now, we need to setup the equation where the cm cancels and nm is left.

52. 52 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm) 1 cm = 0.01 m 1 x 10 -9 m = 1 nm Now, fill-in the value that corresponds with the unit and solve the equation.

53. 53 Dimensional Analysis Problem Convert the quantity from 2.3 x 10 -8 cm to nanometers (nm)

54. 54 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 )

55. 55 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 ) First we will need to determine the conversion factors Mile (mi)  kilometer (km) kilometer (km)  meter (m)

56. 56 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 ) First we will need to determine the conversion factors Mile (mi)  kilometer (km) kilometer (km)  meter (km) Or 1 mile = 1.6093km 1000m = 1 km

57. 57 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 ) Now, we need to setup the equation where the mi cancels and m is left. 1 mile = 1.6093km1000m = 1 km

58. 58 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 ) Now, we need to setup the equation where the mi cancels and m is left. 1 mile = 1.6093km1000m = 1 km Notice, that the units do not cancel, each conversion factor must be “squared”.

59. 59 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 )

60. 60 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 )

61. 61 Dimensional Analysis Problem Convert the quantity from 31,820 mi 2 to square meters (m 2 )

62. 62 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr).

63. 63 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr). Determine the conversion factors Meter (m)  Kilometer (km)Kilometer(km)  Mile(mi) Seconds (s)  Minutes (min)Minutes(min)  Hours (hr)

64. 64 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr). Determine the conversion factors Meter (m)  Kilometer (km)Kilometer(km)  Mile(mi) Seconds (s)  Minutes (min)Minutes(min)  Hours (hr) Or 1 mile = 1.6093 km1000m = 1 km 60 sec = 1 min60 min = 1 hr

65. 65 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr). 1 mile = 1.6093 km1000m = 1 km 60 sec = 1 min60 min = 1 hr

66. 66 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr). 1 mile = 1.6093 km1000m = 1 km 60 sec = 1 min60 min = 1 hr

67. 67 Dimensional Analysis Problem Convert the quantity from 14 m/s to miles per hour (mi/hr). 1 mile = 1.6093 km1000m = 1 km 60 sec = 1 min60 min = 1 hr

68. 68 End of Chapter Problems 1.2, 1.16a, 1.18, 1.20, 1.26, 1.36, 1.38, 1.44, 1.52, 1.63, 1.67