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Modern Chemistry Chapter 2 Homework 2-8 Skills

Presentation on theme: "Modern Chemistry Chapter 2 Measurements and Calculations"— Presentation transcript:

1 Modern Chemistry Chapter 2 Measurements and Calculations
Sections 1 - 3Scientific MethodUnits of MeasurementUsing Scientific Measurements

2 Chapter 2 Section 1 Scientific Method pages 29-32
SystemHypothesisModelTheoryQuantitySIWeightDerived unitVolumeDensityConversion FactorDimensional analysisAccuracyPrecisionPercentage errorSignificant figuresScientific notationDirectly proportionalInversely proportionalChapter VocabularyChapter 2 Section 1 Scientific Method pages 29-32

3 Chapter 2 Section 1 Scientific Method pages 29-32

4 Chapter 2 Section 1 Scientific Method pages 29-32
A logical approach to solving problems byOBSERVING AND COLLECTING DATAFORMULATING HYPOTHESISTESTING HYPOTHESISFORMULATING THEORIESthat are supported by data.Not a fixed series of steps.Chapter 2 Section 1 Scientific Method pages 29-32

5 Scientific Method Image
p. 31Chapter 2 Section 1 Scientific Method pages 29-32

6 Scientific Method Animation
Chapter 2 Section 1 Scientific Method pages 29-32

7 Observation and Collecting Data
What are we studying?A system is a specific portion of matterin a given region of spacethat has been selected for studyduring an experiment or observation.Chapter 2 Section 1 Scientific Method pages 29-32

8 Observation and Collecting Data
use of senses to obtain informationQualitative – descriptiveQuantitative – numericOrganize data and observations into tables and/or graphs.Chapter 2 Section 1 Scientific Method pages 29-32

9 Organizing Data into a Graph
Chapter 2 Section 1 Scientific Method pages 29-32

10 Qualitative and Quantitative Observation Animation
Chapter 2 Section 1 Scientific Method pages 29-32

11 Formulating Hypothesis
Generalizations about data or observations can be used to make a hypothesisA hypothesis is a testable statementOften in an if-then statementA prediction that is the basis for testing by experimentChapter 2 Section 1 Scientific Method pages 29-32

12 Chapter 2 Section 1 Scientific Method pages 29-32
Hypothesis AnimationChapter 2 Section 1 Scientific Method pages 29-32

13 Chapter 2 Section 1 Scientific Method pages 29-32
Testing HypothesisControls – conditions that remain constant (controlled variables)Variable – any condition that changesDriven by the hypothesisTest only one variable at a timeIdentify variables to be held constantChapter 2 Section 1 Scientific Method pages 29-32

14 Chapter 2 Section 1 Scientific Method pages 29-32
TheorizingWhen data from experiments support a hypothesis a theory and model are constructedA model in science ismore than a physical object.It is often an explanation ofhow phenomena occur andhow data or events are relatedChapter 2 Section 1 Scientific Method pages 29-32

15 Chapter 2 Section 1 Scientific Method pages 29-32
Model AnimationChapter 2 Section 1 Scientific Method pages 29-32

16 Chapter 2 Section 1 Scientific Method pages 29-32
TheorizingModels are a part of a theory.A theory isa broad generalizationthat explainsa body of facts or phenomena.not a fact; explains factsmodified with new discoveriesChapter 2 Section 1 Scientific Method pages 29-32

17 Reading Notes #7-15 pages 33-43
Section 1 HomeworkReading Notes #7-15 pages 33-43Chapter 2 Section 1 Scientific Method pages 29-32

18 Chapter 2 Section 2 Units of Measurements pages 33-43

19 Chapter 2 Section 2 Units of Measurements pages 33-43
QUANTITYUNITSTANDARDLengthFootThe king’s footMassKilogramKg prototypea.m.u.1/12th of a carbon-12 atomSomething that has magnitude, size or amountObjects or natural phenomena that are of constant value, easy to preserve and reproduceChapter 2 Section 2 Units of Measurements pages 33-43

20 Chapter 2 Section 2 Units of Measurements pages 33-43
Common SI Units Tablep. 33*Chapter 2 Section 2 Units of Measurements pages 33-43

21 Chapter 2 Section 2 Units of Measurements pages 33-43
SI MeasurementsLe Systeme’ International d’Unitesnot 75,000 use spaces not commasChapter 2 Section 2 Units of Measurements pages 33-43

22 Chapter 2 Section 2 Units of Measurements pages 33-43
Base SI Units Tablep. 34Chapter 2 Section 2 Units of Measurements pages 33-43

23 Chapter 2 Section 2 Units of Measurements pages 33-43
SI Base UnitsComparing Mass and WeightMass is the measure of the amount of mater in an object.Unit = kgWeight is the measure of the gravitational pull on matterUnit = N (newtons)Dependant on gravityChapter 2 Section 2 Units of Measurements pages 33-43

24 Chapter 2 Section 2 Units of Measurements pages 33-43
SI PrefixesgigaG1 Gm = 1 x 109 mmegaM1 Mm = 1 x 106 mkilok1 km = 1000 mhectoh1 hm = 100 mdekada1 dam = 10 m1 m = 1 meterdecid1 dm = 0.1 mcentic1 cm = 0.01mmillim1 mm = 0.001mmicroμ1 μm = 1 x 10-6 mnanon1 nm = 1 x mChapter 2 Section 2 Units of Measurements pages 33-43

25 Chapter 2 Section 2 Units of Measurements pages 33-43
SI Conversions Imagep. 40*Chapter 2 Section 2 Units of Measurements pages 33-43

26 Chapter 2 Section 2 Units of Measurements pages 33-43
Derived SI UnitsDerived Units – a combination of SI unitsExample 1 kg/m∙sec2 = 1 pascal (Pa)Volume – the amount of space occupied by an objectL x W x H = 1m x 1m x 1m = 1m31dm x 1dm x 1dm = 1dm3 = 1 liter1cm x 1cm x 1cm = 1cm3 = 1 mLChapter 2 Section 2 Units of Measurements pages 33-43

27 Chapter 2 Section 2 Units of Measurements pages 33-43
Derived Units Tablep. 36Chapter 2 Section 2 Units of Measurements pages 33-43

28 Chapter 2 Section 2 Units of Measurements pages 33-43
DensityThe ratio of mass to volumeD = M / VUnit = kg/m3 or g/cm3 = g/mLA characteristic physical propertyCan be used to identify a substanceVaries with temperatureChapter 2 Section 2 Units of Measurements pages 33-43

29 Chapter 2 Section 2 Units of Measurements pages 33-43
Density Tablep. 38Chapter 2 Section 2 Units of Measurements pages 33-43

30 Density Formula Animation
Chapter x Section x Section title pages xx-xx

31 Chapter 2 Section 2 Units of Measurements pages 33-43
DensityWhat is the density of a block of marble that occupies 310 cm3 and has a mass of 853 g?Diamond has a density of 3.26g/cm3. What is the mass of a diamond that has a volume of cm3?What is the volume of a sample of liquid mercury that has a mass of 76.2 g, given the density of mercury is 13.6 g/mL?p. 40g/cm g mLChapter 2 Section 2 Units of Measurements pages 33-43

32 Chapter 2 Section 2 Units of Measurements pages 33-43
Conversion FactorsA ratio derived from the equality between two different units that can be used to convert from one unit to anotherChapter 2 Section 2 Units of Measurements pages 33-43

33 Chapter 2 Section 2 Units of Measurements pages 33-43
Conversion FactorsConversion factors always equal 1.The numerator is equal to the denominator.4 quarters1 dollar= 11 kilogram1000 grams= 112 inches1 foot= 1Chapter 2 Section 2 Units of Measurements pages 33-43

34 Conversion Factors Animation
Chapter 2 Section 2 Units of Measurements pages 33-43

35 Chapter 2 Section 2 Units of Measurements pages 33-43
Dimensional AnalysisA mathematical technique that allows you to use units to solve a problem involving measurementsChapter 2 Section 2 Units of Measurements pages 33-43

36 Dimensional Analysis wanted unit # given unit = # wanted unit x
Put in numbers to make the numerator equal to the denominator= # wanted unitxgiven unitChapter 2 Section 2 Units of Measurements pages 33-43

37 Chapter 2 Section 2 Units of Measurements pages 33-43
Dimensional Analysisxxxx=Arrange the units so that all cancel out except the last one, which should be the one you want.Chapter 2 Section 2 Units of Measurements pages 33-43

38 Using Conversion Factors Image
p. 40*Chapter 2 Section 2 Units of Measurements pages 33-43

39 Chapter 2 Section 2 Units of Measurements pages 33-43
Dimensional AnalysisHow many seconds in one week?Chapter 2 Section 2 Units of Measurements pages 33-43

40 Chapter 2 Section 2 Units of Measurements pages 33-43
Dimensional AnalysisExpress a length of m in centimeters and in kilometers.Express a mass of mg in grams.p. 40cm and km gChapter 2 Section 2 Units of Measurements pages 33-43

41 Using Scientific Measurements
Section 3Using Scientific MeasurementsChapter 2 Section 3 Using Scientific Measur. pages 44-57

42 Accuracy and Precision
Accuracy refers to the closeness of measurements to the correct or accepted value of the quantity measuredPrecision refers to the closeness of a set of measurements of the same quantity made the same way.Chapter 2 Section 3 Using Scientific Measur. pages 44-57

43 Accuracy & Precision Darts Animation
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

44 Accuracy and Precision Image
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

45 Chapter 2 Section 3 Using Scientific Measur. pages 44-57
Percent ErrorHigh percent error = low accuracyNegative? Experimental is too lowPositive? Experimental is too highChapter 2 Section 3 Using Scientific Measur. pages 44-57

46 Percent Error Formula Animation
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

47 Chapter 2 Section 3 Using Scientific Measur. pages 44-57
Percent ErrorExpress a length of m in centimeters and in kilometers.Express a mass of mg in grams.p. 40cm and km gChapter 2 Section 3 Using Scientific Measur. pages 44-57

48 Chapter 2 Section 3 Using Scientific Measur. pages 44-57
Errors in MeasurementSkill of the measurerLimitation of instrumentsEstimationChapter 2 Section 3 Using Scientific Measur. pages 44-57

49 Measuring Liquids & Meniscus Animation
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

50 Chapter 2 Section 3 Using Scientific Measur. pages 44-57
certainestimatedPlus or minus one of the estimated decimal placesp. 46Chapter 2 Section 3 Using Scientific Measur. pages 44-57

51 Affectionately called “sig. figs.”
SIGNIFICANTFIGURESSIGNIFICANTFIGURESAffectionately called “sig. figs.”

52 Brought to you by….

53 Nonzero integers always count as significant figures!

54 All the certain number in a measurement plus one estimated figure.
Significant FiguresAll the certain number in a measurement plus one estimated figure.

55 There are three classes of zeros.
There are three classes of zeros.LEADINGTRAILINGCAPTIVE

56 as significant figures.
LEADING ZEROSThese do not countas significant figures.0.00252.5 x 10-3

57 as significant figures.
CAPTIVE ZEROSThese countas significant figures.1.008

58 100 vs. 100. 1.00 x 102 TRAILING ZEROS These do not count
as significant figures…unless there is a decimal point.100 vs. 100.1.00 x 102

59 2 atoms of H in H2O EXACT NUMBERS These are determined by counting.
These have infinite significant figures.2 atoms of H in H2O

60 These answer the question, “What do we round to?”
SIG FIGS INCALCULATIONSThese answer the question,“What do we round to?”There are two different rules:Multiplication & DivisionAddition & Subtraction

61 A team is only as good as its….
PRECISIONA team is only as good as its….worstplayerPractice!Your answer can only be as precise as your least precise (worst) piece of data!

62 MULTIPLICATION & DIVISION
The number of sig figs in the result is the same as the least precise measurement used in the calculation.13.54g /0.40ml =34 g/ml33.85 g/ml

63 ADDITION & SUBTRACTION
The result has the same number of decimal places as the least precise measurement used in the calculation.=13.86+

64 In a series of calculations, round at the very end.
RoundingIn a series of calculations,round at the very end.LESS THANThe preceding digit stays the same.5 & GREATERThe preceding digit is increased by 1.5

65

66 Significant Figures Rules Table
p. 47Chapter 2 Section 3 Using Scientific Measur. pages 44-57

67 Rules for Significant Zeros Animation
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

68 Rounding Rules Animation
Chapter 2 Section 3 Using Scientific Measur. pages 44-57

69 M x 10n Scientific Notation
Greater than or equal to 1 but less than 10A whole numberA negative exponent means the number is small A positive exponent means the number is largeChapter 2 Section 3 Using Scientific Measur. pages 44-57

Испанская церковь гордится тем, что ей принадлежат его останки. Испанская церковь. Беккер отлично знал, что в Испании только одна церковь - римско-католическая.

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