2 Units of Measurement You are making a measurement when you 3/28/2017Units of MeasurementYou are making a measurement when youCheck you weightRead your watchTake your temperatureWeigh a cantaloupeWhat kinds of measurements did you make today?
3 Standards of Measurement 3/28/2017Standards of MeasurementWhen we measure, we use a measuring tool to compare some dimension of an object to a standard.
4 Some Tools for Measurement 3/28/2017Some Tools for Measurement
5 3/28/2017Learning CheckFrom the previous slide, state the tool (s) you would use to measureA. temperature ____________________B. volume ________________________________________C. time ____________________D. weight ____________________
6 3/28/2017SolutionFrom the previous slide, state the tool (s) you would use to measureA. temperature thermometerB. volume measuring cup, graduated cylinderC. time watchD. weight scale
7 Measurement in Chemistry 3/28/2017Measurement in ChemistryIn chemistry wedo experimentsmeasure quantitiesuse numbers to report measurements
8 In every measurement there is a Unit from measuring device 3/28/2017Stating a MeasurementIn every measurement there is aNumberfollowed by aUnit from measuring device
9 3/28/2017Learning CheckWhat is the unit of measurement in each of the following examples?A. The patient’s temperature is 102°F.B. The sack holds 5 lbs of potatoes.C. It is 8 miles from your house to school.D. The bottle holds 2 L of orange soda.
10 Metric System (SI) Is a decimal system based on 10 3/28/2017Metric System (SI)Is a decimal system based on 10Used in most of the worldUsed by scientists and hospitals
11 Units in the Metric System 3/28/2017Units in the Metric Systemlength meter mvolume liter Lmass gram gtemperature Celsius °C
12 Learning Check Identify the measurement in metric units. 3/28/2017Learning CheckIdentify the measurement in metric units.A. John’s height is1) 1.5 yards 2) 6 feet 3) 2 metersB. The volume of saline in the IV bottle is1) 1 liters 2) 1 quart 3) 2 pintsC. The mass of a lemon is1) 12 ounces 2) 145 grams 3) 0.6 pounds
13 Measured Numbers and Significant Figures 3/28/2017MeasurementsMeasured Numbers and Significant Figures
14 3/28/2017Measured NumbersWhen you use a measuring tool to determine a quantity such as your height or weight, the numbers you obtain are called measured numbers.
15 3/28/2017Reading a Meterstick. l I I I I cmFirst digit (known) = ?? cmSecond digit (known) = ? cmThird digit (estimated) betweenLength reported = cmor cmor cm
16 Known + Estimated Digits 3/28/2017Known + Estimated DigitsKnown digits 2 and 7 are 100% certainThe third digit 6 is estimated (uncertain)In the reported length, all three digits(2.76 cm) are significant including the estimated one
17 Learning Check . l8. . . . I . . . . I9. . . .I . . . . I10. . cm 3/28/2017Learning Check. l I I I I cmWhat is the length of the line?1) cm2) cm3) cmHow your answer compare with your neighbor’s answer? Why or why not?
18 Learning Check l5. . . . I . . . . I6. . . .I . . . . I7. . cm 3/28/2017Learning Checkl I I I I cmWhat is the length of the line?1) 6.0 cm2) cm3) cm
19 Zero as a Measured Number 3/28/2017Zero as a Measured Number. l I I I I cmWhat is the length of the line?First digit ?? cmSecond digit ? cmLast (estimated) digit is cm(not to the left or right of .5)
20 Exact Numbers Obtained when you count objects 1 watch 4 pizzas 3/28/2017Exact NumbersObtained when you count objects2 soccer balls1 watch4 pizzasObtained from a defined relationship1 foot = 12 inches1 meters = 100 cmNot obtained with measuring tools
22 Learning Check Classify each of the following as an exact (1) 3/28/2017Learning CheckClassify each of the following as an exact (1)or a measured (2) number.A.___Gold melts at 1064°CB.___1 yard = 3 feetC.___A red blood cell with diameter 6 x 10-4 cmD.___There were 6 hats on the shelfE.___A can of soda contains 355 mL of soda2, 1, 2, 1, 2
23 Significant Figures in Measurement 3/28/2017Significant Figures in MeasurementThe numbers reported in a measurement are limited by the measuring toolSignificant figures in a measurement include the known digits plus one estimated digit
24 Significant Figures Summary 3/28/2017Any digit that is not zero is significant1.234 kg significant figuresZeros between nonzero digits are significant606 m significant figuresZeros to the left of the first nonzero digit are not significant0.08 L significant figureIf a number is greater than 1, then all zeros to the right of the decimal point are significant2.0 mg significant figuresIf a number is less than 1, then only the zeros that are at the end and in the middle of the number are significantg 3 significant figures1.8
25 Counting Significant Figures 3/28/2017Counting Significant FiguresNumber of Significant Figures38.15 cm 45.6 ft 265.6 lb ___m ___Complete: All non-zero digits in a measured number are (significant or not significant).
26 Leading Zeros 0.008 mm 1 0.0156 oz 3 0.0042 lb ____ 0.000262 mL ____ 3/28/2017Leading ZerosNumber of Significant Figures0.008 mm 1oz 3lb ____mL ____Complete: Leading zeros in decimal numbers are (significant or not significant).
27 Sandwiched Zeros Number of Significant Figures 50.8 mm 3 2001 min 4 3/28/2017Sandwiched ZerosNumber of Significant Figures50.8 mm 32001 min 40.702 lb ____m ____Complete: Zeros between nonzero numbers are (significant or not significant).
28 Trailing Zeros Number of Significant Figures 25,000 in. 2 200 yr 1 3/28/2017Trailing ZerosNumber of Significant Figures 25,000 in200 yr 148,600 gal 325,005,000 g ____Complete: Trailing zeros in numbers without decimals are (significant or not significant) if they are serving as place holders.
29 3/28/2017Learning CheckA. Which answers contain 3 significant figures?1) ) ) 4760B. All the zeros are significant in1) ) ) x 103C. 534,675 rounded to 3 significant figures is1) ) 535, ) 5.35 x 105A: 2, 3; B: 2, 3; C: 2, 3
30 Learning Check 2) 400.0 and 40 3) 0.000015 and 150,000 3/28/2017Learning CheckIn which set(s) do both measured numbers contain the same number of significant figures?1) and 22.002) and 403) and 150,000Only 3)
31 Learning Check SF3 A. 0.030 m 1 2 3 B. 4.050 L 2 3 4 C. 0.0008 g 1 2 4 3/28/2017Learning Check SF3State the number of significant figures in each of the following measured/calculated numbers:A mB LC gD mE. 2,080,000 beesA: 2; b: 4; c: 1; d: 3; e: 3
32 Significant Numbers in Calculations 3/28/2017Significant Numbers in CalculationsA calculated answer cannot be more precise than the measuring tool.A calculated answer must match the least precise measurement.Significant figures are needed for final answers from1) adding or subtracting2) multiplying or dividing
33 Adding and Subtracting 3/28/2017Adding and SubtractingThe answer has the same number of decimal places as the measurement with the fewest decimal places.one decimal placetwo decimal places26.54answer one decimal place E.g., = 31should be 26 (assume all numbers are measured numbers)
34 3/28/2017Learning CheckIn each calculation, round the answer to the correct number of significant figures.A =1) ) ) 257B =1) ) ) 40.7A: 2; B: 3
35 Multiplying and Dividing 3/28/2017Multiplying and DividingRound (or add zeros) to the calculated answer until you have the same number of significant figures as the measurement with the fewest significant figures.
36 Learning Check A. 2.19 X 4.2 = 1) 9 2) 9.2 3) 9.198 B. 4.311 ÷ 0.07 = 3/28/2017Learning CheckA X =1) ) )B ÷ =1) ) ) 60C X =X 0.0601) ) )A: 2; B: 3; C: 2
38 Metric Prefixes Increase or decrease basic unit by 10 3/28/2017Metric PrefixesIncrease or decrease basic unit by 10Form new units larger or smaller than the basic unitsIndicate a numerical valueprefix = value1 kilometer = meters1 kilogram = grams
39 Prefixes that Increase A Unit 3/28/2017Prefixes that Increase A UnitPrefix Symbol Valuegiga- Gmega- Mkilo- k
40 Prefixes that Decrease A Unit 3/28/2017Prefixes that Decrease A UnitPrefix Symbol Valuedeci- d 0.1centi- cmilli- mmicro- (mu)nano n
41 Learning Check Match 1) length 2) mass 3) volume 3/28/2017Learning CheckMatch 1) length 2) mass 3) volume____ A. A bag of tomatoes is 4.6 kg.____ B. A person is 2.0 m tall.____ C. A medication contains 0.50 g Aspirin.____ D. A bottle contains 1.5 L of water.A: 2; B: 1; C: 2; D: 3
42 Learning Check 1) millimeters 2) meters 3) kilometers 3/28/2017Learning CheckSelect the unit you would use to measureA. Your height1) millimeters 2) meters 3) kilometersB. Your mass1) milligrams 2) grams 3) kilogramsC. The distance between two cities1) millimeters 2) meters 3) kilometersD. The width of an arteryA: 2; B: 3; C: 3; D: 1
43 Learning Check Indicate the prefix to use for 3/28/2017Learning CheckIndicate the prefix to use for1. A mass that is 1000 times greater than 1 gram1) kilo 2) milli 3) mega2. A length that is 1/100 of 1 meter?1) deci 2) centi 3) milli3. A unit of time that is 1/1000 of a second.1) nanosecond 2) microsecond 3)millisecond1: 1; 2: 2; 3: 3
44 Equalities State the same measurement in two different units length 3/28/2017EqualitiesState the same measurement in two different unitslength10.0 in.25.4 cm
45 Fundamental & Derived SI units and Metric Equalities 3/28/2017Length 1 km = 1000 m 1m = 100 cm 1m = 1000 mmMass 1 kg = g 1 g =Volume 1 kL = L 1L = 100 cL 1L = 1000 mLMatter is anything that takes up space and has massFundamental SI Units (Derived SI units are derived from these base units):
46 Volume – SI derived unit for volume is cubic meter (m3) 3/28/2017Volume – SI derived unit for volume is cubic meter (m3)1 cm3 = (1 x 10-2 m)3 = 1 x 10-6 m31 dm3 = (1 x 10-1 m)3 = 1 x 10-3 m31 L = 1000 mL = 1000 cm3 = 1 dm31 mL = 1 cm3
47 Learning Check C. 0.1 L = 1 ___ 1) mL 2) cL 3) dL 3/28/2017Learning CheckA m = 1 ___ 1) mm 2) km 3) dmB g = 1 ___ 1) mg 2) kg 3) dgC L = 1 ___ 1) mL 2) cL 3) dLD m = 1 ___ 1) mm 2) cm 3) dmA: 2; B: 1; C: 3; D: 2
48 Learning Check Give the value of the following units: A. 1 kg = ____ g 3/28/2017Learning CheckGive the value of the following units:A. 1 kg = ____ g1) 10 g 2) 100 g 3) gB. 1 mm = ____ m1) m 2) m 3) 0.1 mA: 3; B: 1
49 Some American Equalities 3/28/2017Some American Equalities1 ft = inches1 lb = 16 oz1 quart = pints1 quart = 4 cupsWhy are the quantities in each pair equal?1 ft = 12 in; 1 qt = 2 pints
50 Some Metric-American Equalities 3/28/2017Some Metric-American Equalities1 in. = 2.54 cm1 qt = 946 mL1 L = 1.06 qt1 lb = 454 g1 kg = 2.20 lbRemember these for exams.
51 Equalities given in a Problem 3/28/2017Equalities given in a ProblemExample 1At the store, the price of one pound of red peppers is $2.39.Equality: 1 lb red peppers = $2.39Example 2At the gas station, one gallon of gas is $1.34.Equality: 1 gallon of gas = $1.34
52 3/28/2017Accuracy vs. PrecisionAccuracy – how close a measurement is to the true valuePrecision – how close a set of measurements are to each otheraccurate&preciseprecisebutnot accuratenot accurate¬ precise
53 3/28/2017Conversion FactorsFractions in which the numerator and denominator are quantities expressed in an equality between those unitsExample: in. = 2.54 cmFactors: 1 in and cm2.54 cm in.
54 Learning Check A. Liters and mL B. Hours and minutes 3/28/2017Learning CheckWrite conversion factors that relate each of the following pairs of units:A. Liters and mLB. Hours and minutesD. Meters and kilometers
55 Solution A. quarts and mL 1 L = 1000 mL 1 L and 1000 mL 1000 mL 1 L 3/28/2017SolutionA. quarts and mL 1 L = 1000 mL1 L and mL1000 mL LB. hours and minutes 1 hr = 60 min1 hr and min60 min hrC. meters and kilometers 1 km = 1000 m1 km and m1000 m km
56 Problem Solving Using Conversion Factors 3/28/2017MeasurementsProblem Solving Using Conversion Factors
57 Initial and Final Units 3/28/2017Initial and Final Units1. A person has a height of 2.0 meters. What is that height in inches?Initial unit = m Final unit = _______2) Blood has a density of 1.05 g/mL. If a person lost 0.30 pints of blood at 18°C, how many ounces of blood would that be?Initial = pints Final unit = _______inches1: in; 2: ozounces
58 How many minutes are in 2.5 hours? 3/28/2017How many minutes are in 2.5 hours?Initial unit2.5 hrConversion Finalfactor unit2.5 hr x min = min1 hrcancel Answer (2 SF)
59 3/28/2017Learning CheckA rattlesnake is 2.44 m long. How long is the snake in cm?1) cm2) 244 cm3) 24.4 cm
60 Solution A rattlesnake is 2.44 m long. How long is the snake in cm? 3/28/2017SolutionA rattlesnake is 2.44 m long. How long is the snake in cm?2) 244 cm2.44 m x cm = 244 cm1 m
61 Learning Check How many seconds are in 1.4 days? 3/28/2017Learning CheckHow many seconds are in 1.4 days?Unit plan: days hr min seconds1.4 days x 24 hr x ??1 day
62 Solution CF2 Unit plan: days hr min seconds 2 SF Exact 3/28/2017Solution CF2Unit plan: days hr min seconds2 SF Exact1.4 day x 24 hr x 60 min x 60 sec1 day hr min= 1.2 x 105 sec
63 Unit Check What is wrong with the following setup? 3/28/2017Unit CheckWhat is wrong with the following setup?1.4 day x 1 day x min x 60 sec24 hr hr min
64 Unit Check 1.4 day x 1 day x 60 min x 60 sec 24 hr 1 hr 1 min 3/28/2017Unit Check1.4 day x 1 day x min x 60 sec24 hr hr minUnits = day2-sec/hr2 Not the final unit needed
65 3/28/2017Learning CheckAn adult human has 4650 mL of blood. How many gallons of blood is that?Unit plan: mL qt gallonEqualities: 1 quart = 946 mL1 gallon = 4 quartsYour Setup:
66 Solution Unit plan: mL qt gallon Setup: 3/28/2017SolutionUnit plan: mL qt gallonSetup:4650 mL x qt x 1 gal = gal946 mL qt3 SF equality exact SF
67 Steps to Problem Solving 3/28/2017Steps to Problem SolvingRead problemIdentify dataWrite down a unit plan from the initial unitto the desired unitSelect conversion factorsChange initial unit to desired unitCancel units and checkDo math on calculatorGive an answer using correct significant figures
68 3/28/2017Learning CheckIf the ski pole is 3.0 feet in length, how long is the ski pole in mm?
69 3/28/2017Solution3.0 ft x 12 in x cm x 10 mm =1 ft in cm
70 3/28/2017Learning CheckIf your pace on a treadmill is 65 meters per minute, how many seconds will it take for you to walk a distance of feet?
71 Solution Initial 8450 ft x 12 in. x 2.54 cm x 1 m 1 ft 1 in. 100 cm 3/28/2017SolutionInitial8450 ft x 12 in. x cm x 1 m1 ft in cmx 1 min x 60 sec = sec65 m min final (2 SF)
73 Density Density compares the mass of an object to its volume 3/28/2017DensityDensity compares the mass of an object to its volumeD = mass = g or gvolume mL cm3Note: 1 mL = 1 cm3
74 Learning Check D1 Osmium is a very dense metal. What is its 3/28/2017Learning Check D1Osmium is a very dense metal. What is itsdensity in g/cm3 if g of the metal occupiesa volume of 2.22cm3?1) g/cm32) 22.5 g/cm33) 111 g/cm3
75 3/28/2017Solution2) Placing the mass and volume of the osmium metal into the density setup, we obtainD = mass = g =volume 2.22 cm3= g/cm3 = g/cm3
76 3/28/2017Volume DisplacementA solid displaces a matching volume of water when the solid is placed in water.33 mL25 mL
77 Learning Check 1) 0.2 g/ cm3 2) 6 g/m3 3) 252 g/cm3 3/28/2017Learning CheckWhat is the density (g/cm3) of 48 g of a metal if the metal raises the level of water in a graduated cylinder from 25 mL to 33 mL?1) 0.2 g/ cm ) 6 g/m ) g/cm333 mL25 mL
78 Solution 2) 6 g/cm3 Volume (mL) of water displaced 3/28/2017Solution2) 6 g/cm3Volume (mL) of water displaced= mL mL = mLVolume of metal (cm3)= 8 mL x 1 cm3 = cm31 mLDensity of metal =mass = 48 g = 6 g/cm3volume cm3
79 Learning Check3 K V W V K W W V K 1) 2) 3) 3/28/2017Learning Check3Which diagram represents the liquid layers in the cylinder?(K) Karo syrup (1.4 g/mL), (V) vegetable oil (0.91 g/mL,) (W) water (1.0 g/mL)1) ) )Answer: 1;KVWKVWWVK
80 Density as Conversion Factors 3/28/2017Density as Conversion FactorsA substance has a density of 3.8 g/mL.Density = 3.8 g/mLEquality g = 1 mLConversion factors.3.8 g and mL1 mL g
81 3/28/2017Density ConnectionsMass Volumekg Lg mL (cm3)mg
82 3/28/2017Learning CheckThe density of octane, a component of gasoline, is g/mL. What is the mass, in kg, of 875 mL of octane?1) kg2) 614 kg3) 1.25 kg
83 Solution 1) 0.614 kg Unit plan: mL g kg 3/28/2017Solution1) kgUnit plan: mL g kgEqualities: 1 mL = g and 1 kg = 1000 gSetup:875 mL x g x kg = kg1 mL gdensity metricfactor factor
84 3/28/2017Learning CheckIf blood has a density of 1.05 g/mL, how many liters of blood are donated if 575 g of blood are given?1) L2) L3) L
85 Solution Unit Plan: g mL L 575 g x 1 mL x 1 L = 0.548 L 1.05 g 1000 mL 3/28/2017Solution1)Unit Plan: g mL L575 g x mL x 1 L = L1.05 g mL
86 3/28/2017Learning CheckA group of students collected 125 empty aluminum cans to take to the recycling center. If 21 cans make 1.0 pound of aluminum, how many liters of aluminum (D=2.70 g/cm3) are obtained from the cans?1) 1.0 L 2) 2.0 L 3) 4.0 L
87 Solution 1 cm3 1000 mL 1) 1.0 L 125 cans x 1.0 lb x 454 g x 1 cm3 3/28/2017Solution1) 1.0 L125 cans x 1.0 lb x 454 g x 1 cm321 cans lb gx 1 mL x L = 1.0 L1 cm mL
88 3/28/2017Learning CheckYou have 3 metal samples. Which one will displace the greatest volume of water?Discuss your choice with another student.25 g Al2.70 g/mL45 g of gold19.3 g/mL75 g of Lead11.3 g/mL
89 3/28/2017Solution1) 25 g Al x mL = mL g25 g Al2.70 g/mL
90 Measuring Temperature 3/28/2017Chapter 1Measuring Temperature
91 Temperature Particles are always moving. 3/28/2017TemperatureParticles are always moving.When you heat water, the water molecules move faster.When molecules move faster, the substance gets hotter.When a substance gets hotter, its temperature goes up.
92 Learning Check Suppose you place water in a freezer. 3/28/2017Learning CheckSuppose you place water in a freezer.A. The water particles move1) faster 2) slower ) the sameB. The water will get1) hotter 2) colder ) stay the sameC. The temperature of the water will be1) higher 2) lower ) the sameA: 2; b: 2; c: 2
93 Temperature Measures the hotness or coldness of an object 3/28/2017TemperatureMeasures the hotness or coldness of an objectDetermined by using a thermometer that contains a liquid that expands with heat and contracts with cooling.
95 Units of Temperature between Boiling and Freezing 3/28/2017Units of Temperature between Boiling and FreezingFahrenheit Celsius KelvinWater boils °F °C K180° 100°C KWater freezes 32°F °C K
96 Learning Check A. Temperature of freezing water 1) 0°F 2) 0°C 3) 0 K 3/28/2017Learning CheckA. Temperature of freezing water1) 0°F ) 0°C ) 0 KB. Temperature of boiling water1) 100°F ) 32°F ) 373KC. Number of Celsius units between theboiling and freezing points of water1) ) ) 273A: 2; B: 3; C: 1
97 Fahrenheit Formula 180°F = 9°F = 1.8°F 100°C 5°C 1°C 3/28/2017Fahrenheit Formula180°F = °F = 1.8°F °C °C 1°CZero point: 0°C = 32°F°F = 9/5 (T°C)or°F = 1.8 (T°C)
99 Temperature Conversions 3/28/2017Temperature ConversionsA person with hypothermia has a body temperature of 29.1°C. What is the body temperature in °F?°F = (29.1°C)exact tenth's exact== 84.4°Ftenth’s
100 Learning Check 1) 73.8 °C 2) 58.8 °C 3) 41.0 °C 3/28/2017Learning CheckThe normal temperature of a chickadee is 105.8°F. What is that temperature in °C?1) °C2) °C3) °C
107 3/28/2017Physical or Chemical?A physical change does not alter the composition or identity of a substance.ice meltingsugar dissolvingin waterPhase ChangeA chemical change alters the composition or identity of the substance(s) involved.hydrogen burns in air to form water
108 Extensive and Intensive Properties 3/28/2017Extensive and Intensive PropertiesAn extensive property of a material depends upon how much matter is is being considered.masslengthvolumeAn intensive property of a material does not depend upon how much matter is being considered.densitytemperaturecolor
109 Matter - anything that occupies space and has mass. 3/28/2017Matter - anything that occupies space and has mass.mass – measure of the quantity of matterSI unit of mass is the kilogram (kg)1 kg = 1000 g = 1 x 103 gweight – force that gravity exerts on an objectweight = c x masson earth, c = 1.0on moon, c ~ 0.1A 1 kg bar will weigh1 kg on earth0.1 kg on moon