Presentation on theme: "CHEMISTRY Matter and Change"— Presentation transcript:
1 CHEMISTRY Matter and Change Chapter 2: Analyzing Data
2 Table Of Contents Section 2.1 Units and Measurements CHAPTER2Table Of ContentsSection 2.1 Units and MeasurementsSection 2.2 Scientific Notation and Dimensional AnalysisSection 2.3 Uncertainty in DataSection 2.4 Representing DataClick a hyperlink to view the corresponding slides.Exit
3 Units and Measurements SECTION2.1Units and MeasurementsDefine SI base units for time, length, mass, and temperature.Explain how adding a prefix changes a unit.Compare the derived units for volume and density.mass: a measurement that reflects the amount of matter an object contains
4 Units and Measurements SECTION2.1Units and Measurementsbase unitsecondmeterkilogramkelvinderived unitliterdensityChemists use an internationally recognized system of units to communicate their findings.
5 Units and Measurements SECTION2.1Units and MeasurementsUnitsSystème Internationale d'Unités (SI) is an internationally agreed upon system of measurements.A base unit is a defined unit in a system of measurement that is based on an object or event in the physical world, and is independent of other units.
6 Units and Measurements Units and Measurements SECTION2.1SECTION2.1Units and MeasurementsUnits and MeasurementsUnits (cont.)
7 Units and Measurements SECTION2.1Units and MeasurementsUnits (cont.)
8 Units and Measurements SECTION2.1Units and MeasurementsUnits (cont.)The SI base unit of time is the second (s), based on the frequency of radiation given off by a cesium-133 atom.The SI base unit for length is the meter (m), the distance light travels in a vacuum in 1/299,792,458th of a second.The SI base unit of mass is the kilogram (kg), about 2.2 pounds
9 Units and Measurements SECTION2.1Units and MeasurementsUnits (cont.)The SI base unit of temperature is the kelvin (K).Zero kelvin is the point where there is virtually no particle motion or kinetic energy, also known as absolute zero.Two other temperature scales are Celsius and Fahrenheit.
10 Units and Measurements SECTION2.1Units and MeasurementsDerived UnitsNot all quantities can be measured with SI base units.A unit that is defined by a combination of base units is called a derived unit.
11 Units and Measurements SECTION2.1Units and MeasurementsDerived Units (cont.)Volume is measured in cubic meters (m3), but this is very large. A more convenient measure is the liter, or one cubic decimeter (dm3).
12 Units and Measurements SECTION2.1Units and MeasurementsDerived Units (cont.)Density is a derived unit, g/cm3, the amount of mass per unit volume.The density equation is density = mass/volume.
13 Which of the following is a derived unit? SECTION2.1Section CheckWhich of the following is a derived unit?A. yardB. secondC. literD. kilogram
14 What is the relationship between mass and volume called? SECTION2.1Section CheckWhat is the relationship between mass and volume called?A. densityB. spaceC. matterD. weight
16 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisExpress numbers in scientific notation.Convert between units using dimensional analysis.quantitative data: numerical information describing how much, how little, how big, how tall, how fast, and so on
17 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional Analysisscientific notationdimensional analysisconversion factorScientists often express numbers in scientific notation and solve problems using dimensional analysis.
18 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisScientific NotationScientific notation can be used to express any number as a number between 1 and 10 (known as the coefficient) multiplied by 10 raised to a power (known as the exponent).Carbon atoms in the Hope Diamond = 4.6 x 10234.6 is the coefficient and 23 is the exponent.
19 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisScientific Notation (cont.)Count the number of places the decimal point must be moved to give a coefficient between 1 and 10.The number of places moved equals the value of the exponent.The exponent is positive when the decimal moves to the left and negative when the decimal moves to the right.800 = 8.0 102= 3.43 10–5
20 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisScientific Notation (cont.)Addition and subtractionExponents must be the same.Rewrite values to make exponents the same.Ex x x 1017, you must rewrite one of these numbers so their exponents are the same. Remember that moving the decimal to the right or left changes the exponent.2.840 x x 1018Add or subtract coefficients.Ex x x 1017 = 3.2 x 1018
21 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisScientific Notation (cont.)Multiplication and divisionTo multiply, multiply the coefficients, then add the exponents.Ex. (4.6 x 1023)(2 x 10-23) = 9.2 x 100To divide, divide the coefficients, then subtract the exponent of the divisor from the exponent of the dividend.Ex. (9 x 107) ÷ (3 x 10-3) = 3 x 1010Note: Any number raised to a power of 0 is equal to 1: thus, 9.2 x 100 is equal to 9.2.
22 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisDimensional AnalysisDimensional analysis is a systematic approach to problem solving that uses conversion factors to move, or convert, from one unit to another.A conversion factor is a ratio of equivalent values having different units.
23 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisDimensional Analysis (cont.)Writing conversion factorsConversion factors are derived from equality relationships, such as 1 dozen eggs = 12 eggs.Percentages can also be used as conversion factors. They relate the number of parts of one component to 100 total parts.
24 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisDimensional Analysis (cont.)Using conversion factorsA conversion factor must cancel one unit and introduce a new one.
25 SECTION2.2Section CheckWhat is a systematic approach to problem solving that converts from one unit to another?A. conversion ratioB. conversion factorC. scientific notationD. dimensional analysis
26 SECTION2.2Section CheckWhich of the following expresses 9,640,000 in the correct scientific notation?A 104B 105C × 106D 610
28 Uncertainty in Data Define and compare accuracy and precision. SECTION2.3Uncertainty in DataDefine and compare accuracy and precision.Describe the accuracy of experimental data using error and percent error.Apply rules for significant figures to express uncertainty in measured and calculated values.experiment: a set of controlled observations that test a hypothesis
29 Uncertainty in Data accuracy precision error percent error SECTION2.3Uncertainty in Dataaccuracyprecisionerrorpercent errorsignificant figuresMeasurements contain uncertainties that affect how a result is presented.
30 Accuracy and Precision SECTION2.3Uncertainty in DataAccuracy and PrecisionAccuracy refers to how close a measured value is to an accepted value.Precision refers to how close a series of measurements are to one another.
31 Accuracy and Precision (cont.) SECTION2.3Uncertainty in DataAccuracy and Precision (cont.)Error is defined as the difference between an experimental value and an accepted value.
32 Accuracy and Precision (cont.) SECTION2.3Uncertainty in DataAccuracy and Precision (cont.)The error equation is error = experimental value – accepted value.Percent error expresses error as a percentage of the accepted value.
33 Uncertainty in Data Significant Figures SECTION2.3Uncertainty in DataSignificant FiguresOften, precision is limited by the tools available.Significant figures include all known digits plus one estimated digit.
34 Significant Figures (cont.) SECTION2.3Uncertainty in DataSignificant Figures (cont.)Rules for significant figuresRule 1: Nonzero numbers are always significant.Rule 2: Zeros between nonzero numbers are always significant.Rule 3: All final zeros to the right of the decimal are significant.Rule 4: Placeholder zeros are not significant. To remove placeholder zeros, rewrite the number in scientific notation.Rule 5: Counting numbers and defined constants have an infinite number of significant figures.
35 Uncertainty in Data Rounding Numbers SECTION2.3Uncertainty in DataRounding NumbersCalculators are not aware of significant figures.Answers should not have more significant figures than the original data with the fewest figures, and should be rounded.
36 Rounding Numbers (cont.) SECTION2.3Uncertainty in DataRounding Numbers (cont.)Rules for roundingRule 1: If the digit to the right of the last significant figure is less than 5, do not change the last significant figure.Rule 2: If the digit to the right of the last significant figure is greater than 5, round up the last significant figure.Rule 3: If the digits to the right of the last significant figure are a 5 followed by a nonzero digit, round up the last significant figure.
37 Rounding Numbers (cont.) SECTION2.3Uncertainty in DataRounding Numbers (cont.)Rules for rounding (cont.)Rule 4: If the digits to the right of the last significant figure are a 5 followed by a 0 or no other number at all, look at the last significant figure. If it is odd, round it up; if it is even, do not round up.
38 Rounding Numbers (cont.) SECTION2.3Uncertainty in DataRounding Numbers (cont.)Addition and subtractionRound the answer to the same number of decimal places as the original measurement with the fewest decimal places.Multiplication and divisionRound the answer to the same number of significant figures as the original measurement with the fewest significant figures.
39 SECTION2.3Section CheckDetermine the number of significant figures in the following: 8,200, 723.0, and 0.01.A. 4, 4, and 3B. 4, 3, and 3C. 2, 3, and 1D. 2, 4, and 1
40 SECTION2.3Section CheckA substance has an accepted density of 2.00 g/L. You measured the density as 1.80 g/L. What is the percent error?A. 20%B. –20%C. 10%D. 90%
42 Representing Data Create graphics to reveal patterns in data. SECTION2.4Representing DataCreate graphics to reveal patterns in data.independent variable: the variable that is changed during an experimentInterpret graphs.graphGraphs visually depict data, making it easier to see patterns and trends.
43 Representing Data Graphing SECTION2.4Representing DataGraphingA graph is a visual display of data that makes trends easier to see than in a table.
44 Representing Data Graphing (cont.) SECTION2.4Representing DataGraphing (cont.)A circle graph, or pie chart, has wedges that visually represent percentages of a fixed whole.
45 Representing Data Graphing (cont.) SECTION2.4Representing DataGraphing (cont.)Bar graphs are often used to show how a quantity varies across categories.
46 Representing Data Graphing (cont.) SECTION2.4Representing DataGraphing (cont.)On line graphs, independent variables are plotted on the x-axis and dependent variables are plotted on the y-axis.
47 Representing Data Graphing (cont.) SECTION2.4Representing DataGraphing (cont.)If a line through the points is straight, the relationship is linear and can be analyzed further by examining the slope.
48 Representing Data Interpreting Graphs SECTION2.4Representing DataInterpreting GraphsInterpolation is reading and estimating values falling between points on the graph.Extrapolation is estimating values outside the points by extending the line.
49 Interpreting Graphs (cont.) SECTION2.4Representing DataInterpreting Graphs (cont.)This graph shows important ozone measurements and helps the viewer visualize a trend from two different time periods.
50 ____ variables are plotted on the ____-axis in a line graph. SECTION2.4Section Check____ variables are plotted on the ____-axis in a line graph.A. independent, xB. independent, yC. dependent, xD. dependent, z
51 What kind of graph shows how quantities vary across categories? SECTION2.4Section CheckWhat kind of graph shows how quantities vary across categories?A. pie chartsB. line graphsC. Venn diagramsD. bar graphs
53 Analyzing Data Chemistry Online Study Guide Chapter Assessment ResourcesChemistry OnlineStudy GuideChapter AssessmentStandardized Test Practice
54 Units and Measurements SECTION2.1Units and MeasurementsStudy GuideKey ConceptsSI measurement units allow scientists to report data to other scientists.Adding prefixes to SI units extends the range of possible measurements.To convert to Kelvin temperature, add 273 to the Celsius temperature. K = °C + 273Volume and density have derived units. Density, which is a ratio of mass to volume, can be used to identify an unknown sample of matter.
55 Scientific Notation and Dimensional Analysis SECTION2.2Scientific Notation and Dimensional AnalysisStudy GuideKey ConceptsA number expressed in scientific notation is written as a coefficient between 1 and 10 multiplied by 10 raised to a power.To add or subtract numbers in scientific notation, the numbers must have the same exponent.To multiply or divide numbers in scientific notation, multiply or divide the coefficients and then add or subtract the exponents, respectively.Dimensional analysis uses conversion factors to solve problems.
56 Uncertainty in Data Key Concepts SECTION2.3Uncertainty in DataStudy GuideKey ConceptsAn accurate measurement is close to the accepted value. A set of precise measurements shows little variation.The measurement device determines the degree of precision possible.Error is the difference between the measured value and the accepted value. Percent error gives the percent deviation from the accepted value. error = experimental value – accepted value
57 Uncertainty in Data Key Concepts SECTION2.3Uncertainty in DataStudy GuideKey ConceptsThe number of significant figures reflects the precision of reported data.Calculations should be rounded to the correct number of significant figures.
58 Representing Data Key Concepts SECTION2.4Representing DataStudy GuideKey ConceptsCircle graphs show parts of a whole. Bar graphs show how a factor varies with time, location, or temperature.Independent (x-axis) variables and dependent (y-axis) variables can be related in a linear or a nonlinear manner. The slope of a straight line is defined as rise/run, or ∆y/∆x.Because line graph data are considered continuous, you can interpolate between data points or extrapolate beyond them.
59 CHAPTER2Analyzing DataChapter AssessmentWhich of the following is the SI derived unit of volume?A. gallonB. quartC. m3D. kilogram
60 Analyzing Data Which prefix means 1/10th? A. deci- B. hemi- C. kilo- CHAPTER2Analyzing DataChapter AssessmentWhich prefix means 1/10th?A. deci-B. hemi-C. kilo-D. centi-
61 Analyzing Data Divide 6.0 109 by 1.5 103. A. 4.0 106 CHAPTER2Analyzing DataChapter AssessmentDivide 6.0 109 by 1.5 103.A. 4.0 106B. 4.5 103C. 4.0 103D. 4.5 106
62 Analyzing Data Round 2.3450 to 3 significant figures. A. 2.35 B. 2.345 CHAPTER2Analyzing DataChapter AssessmentRound to 3 significant figures.A. 2.35BC. 2.34D. 2.40
63 CHAPTER2Analyzing DataChapter AssessmentThe rise divided by the run on a line graph is the ____.A. x-axisB. slopeC. y-axisD. y-intercept
64 Analyzing Data Which is NOT an SI base unit? A. meter B. second CHAPTER2Analyzing DataChapter AssessmentWhich is NOT an SI base unit?A. meterB. secondC. literD. kelvin
65 Analyzing Data Which value is NOT equivalent to the others? A. 800 m CHAPTER2Analyzing DataStandardized Test PracticeWhich value is NOT equivalent to the others?A. 800 mB. 0.8 kmC. 80 dmD. 8.0 x 104 cm
66 CHAPTER2Analyzing DataStandardized Test PracticeFind the solution with the correct number of significant figures: 25 0.25A. 6.25B. 6.2C. 6.3D
67 CHAPTER2Analyzing DataStandardized Test PracticeHow many significant figures are there in meters?A. 4B. 5C. 6D. 11
68 Analyzing Data Which is NOT a quantitative measurement of a liquid? CHAPTER2Analyzing DataStandardized Test PracticeWhich is NOT a quantitative measurement of a liquid?A. colorB. volumeC. massD. density
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