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Units of MeasurementUnits of Measurement
AgendaAgenda Review elementsReview elements Lab Reports TuesdayLab Reports Tuesday SongSong Notes on Units of Measurement & SNNotes on Units of Measurement & SN HomeworkHomework
FFfluorinefluorine
OOoxygenoxygen
seleniumseleniumSeSe
NNnitrogennitrogen
chlorinechlorineClCl
SSsulfursulfur
PPphosphorusphosphorus
BrBrbrominebromine
strontiumstrontiumSrSr
IIIodineIodine
arsenicarsenicAsAs
GaGagalliumgallium
aluminumaluminumAlAl
Percent error formula?Percent error formula?
Units of MeasurementUnits of MeasurementDate:Date:
SongSong
SI UNITSSI UNITS
International System of UnitsInternational System of Units Measurements used around the world so Measurements used around the world so
results are comparable.results are comparable.
Base UnitsBase Units
How would you define base units?How would you define base units?
Basic unit of measurementBasic unit of measurement
LengthLength
Meter, mMeter, m
MassMass
Kilogram, kgKilogram, kg
Amount of SubstanceAmount of Substance
Mole, molMole, mol
TemperatureTemperature Kelvin, KKelvin, K
NO degree sign!NO degree sign!
Absolute Temperature Absolute Temperature no negative # no negative # At absolute 0, all molecular motion stopsAt absolute 0, all molecular motion stops
Celsius to KelvinCelsius to Kelvin ooC + 273 = KC + 273 = K
Celsius to FahrenheitCelsius to Fahrenheit ooF = (9/5*F = (9/5*ooC) + 32C) + 32
Derived UnitsDerived Units
DefineDefine
A combination of base unitsA combination of base units
VolumeVolume
mm33
Length x width x heightLength x width x height
Not very practical unit so we’ll use LNot very practical unit so we’ll use L
1 cm1 cm33 = 1 mL = 1 mL 1000 L = 1 m1000 L = 1 m33
DensityDensity
Mass / volumeMass / volume Kg/mKg/m33
More practical g/mLMore practical g/mL
PressurePressure
Force / AreaForce / Area
mmHg, torr, kPa, atmmmHg, torr, kPa, atm
Reliability of MeasurementsReliability of Measurements
Accuracy: the closeness of a Accuracy: the closeness of a singlesingle measurement to its true value.measurement to its true value. Hitting the bullseye.Hitting the bullseye.
Precision: the closeness of a Precision: the closeness of a setset of values of values to each other.to each other.
Measurement ExplorationMeasurement Exploration
Which measuring devices are more Which measuring devices are more precise?precise?
Basic FormulaBasic Formula
A * 10A * 10exponentexponent
A number between 1 and 10A number between 1 and 10
If original number > than 1, exponent +If original number > than 1, exponent + If original # < than 1, exponent -If original # < than 1, exponent -
PracticePractice
30003000 26530002653000 5460054600 130130 0.0000560.000056 0.004560.00456 0.078690.07869 3.14159263.1415926
HomeworkHomework