## 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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