Units of MeasurementUnits of Measurement2.22.2

DefinitionsDefinitions Weight Weight –measure of the gravitational –measure of the gravitational

pull on matterpull on matter Diff between mass and weightDiff between mass and weight QuantityQuantity – something that has – something that has

magnitude, size or amountmagnitude, size or amount Every measurement must have a unitEvery measurement must have a unit SISI-Le Syst-Le Systèème International d’Unitme International d’Unitèèss We use 7 base units and prefixes to We use 7 base units and prefixes to

express all unitsexpress all units

Quantity Symbol Unit Abbreviation

Length l Meter m

Mass m Kilogram kg

Time t Second s

Thermodynamic Temperature

T Kelvin k

Amount of a Substance

n Mole mol

Electric Current I Ampere A

Luminous Velocity

Iυ Candela cd

Mega - M 1 000 000 (b.u.) = 1M(b.u.) Kilo - k 1 000 (b.u.) = 1k(b.u.) hecto - h 100 (b.u.) = 1h(b.u.) deka - da 10 (b.u.) = 1da(b.u.)

Base Unit deci - d 10 d(b.u.) = 1 (b.u.) centi - c 100 c(b.u.) = 1 (b.u.) milli - m 1 000 m(b.u.) = 1 (b.u.) micro - µ 1 000 000 µ(b.u.) = 1 (b.u.) nano - n1 000 000 000 n(b.u.)=1 (b.u.)

Derived UnitsDerived Units

Combination of SI base unitsCombination of SI base units Examples – mExamples – m33, g/cm, g/cm33, kg/mol, kg/mol VolumeVolume – the amount of space – the amount of space

occupied by an objectoccupied by an object 1000mL = 1 L = 1000cm1000mL = 1 L = 1000cm33

Conversion FactorsConversion Factors

Ratio derived from the equality b/t 2 Ratio derived from the equality b/t 2 different units that can be used to different units that can be used to convert from 1 unit to anotherconvert from 1 unit to another

Ex: there are 4 quarters in 1 dollarEx: there are 4 quarters in 1 dollar Dimensional analysis – math Dimensional analysis – math

technique that allows you to use technique that allows you to use units to solve problems involving units to solve problems involving measurmentsmeasurments

Conversion FactorsConversion Factors Quarters and dollars conversion Quarters and dollars conversion

factor – 4 quarters = 1 dollarfactor – 4 quarters = 1 dollar Convert 18 quarters to dollarsConvert 18 quarters to dollars Start with what you knowStart with what you know What you are going to goes in the What you are going to goes in the

top and coming from goes in the top and coming from goes in the bottombottom

Convert 3 dollars to quartersConvert 3 dollars to quarters

ConversionsConversionsConvert 45 minutes to hours.Convert 45 minutes to hours.Convert 2.5 hours to minutes.Convert 2.5 hours to minutes.Convert 100 millimeters to Convert 100 millimeters to

metersmeters1 meter = 1000millimeters1 meter = 1000millimetersConvert 3 hours to secondsConvert 3 hours to seconds

ConversionsConversionsConvert 0.12 kg to mgConvert 0.12 kg to mgMust convert to base unit first if Must convert to base unit first if

going from one side to the other.going from one side to the other.Convert 130 cm to MmConvert 130 cm to Mm

Conversions with Derived UnitsConversions with Derived Units

Convert 60 miles/hour to Convert 60 miles/hour to kilometers per secondkilometers per second

1 mile = 1.609 kilometers1 mile = 1.609 kilometers How many grams per milliliter are How many grams per milliliter are

there in 34 kilograms per literthere in 34 kilograms per liter

DensityDensity The ratio of mass to volumeThe ratio of mass to volume D = D = mm Know this Know this

vv equation!!!equation!!! Typically expressed as g/cmTypically expressed as g/cm33. . Predict the order of the following from Predict the order of the following from

the most dense to the lease dense…the most dense to the lease dense… Milk, mercury, gasoline, ice, a Milk, mercury, gasoline, ice, a

diamond, a corkdiamond, a cork

DensityDensity

Silver BraceletSilver Bracelet Mass is 100.0 g and when it Mass is 100.0 g and when it

displaces water, volume is 20.5 displaces water, volume is 20.5 cmcm33

Density of silver is 10.5 g/cmDensity of silver is 10.5 g/cm33

Is this a silver bracelet?Is this a silver bracelet?

Density CalculationsDensity Calculations

A piece of an unknown material A piece of an unknown material has a mass of 5.85 g and a has a mass of 5.85 g and a volume of 7.57 cmvolume of 7.57 cm33.  What is the .  What is the density of the material?density of the material?

Density CalculationsDensity Calculations

D = D = mm

vv D = D = m m = = 5.85 g5.85 g

v 7.57 cmv 7.57 cm33

Density = 0.77 g/cmDensity = 0.77 g/cm33

Density calculationsDensity calculations

A 200 g piece of metal has a volume A 200 g piece of metal has a volume of 25 cmof 25 cm33. Calculate the density of . Calculate the density of the metal.the metal.

An unknown mass of silicon An unknown mass of silicon occupies a volume of 350 cmoccupies a volume of 350 cm33. . Calculate the mass of Si knowing Calculate the mass of Si knowing that the density of Si is 2.34 g/cmthat the density of Si is 2.34 g/cm33..

DensityDensity

What is the volume that a 50 What is the volume that a 50 gram piece of gold occupies? gram piece of gold occupies? The density of gold is The density of gold is 19.30g/cm19.30g/cm33..

DensityDensity

A block of lead with dimensions of A block of lead with dimensions of 2.0dm x 8.0cm x 35mm, has a 2.0dm x 8.0cm x 35mm, has a mass of 6.356kg. Calculate the mass of 6.356kg. Calculate the density of lead in g/cmdensity of lead in g/cm33..

DensityDensity

A flask weighs 345.8 g and is A flask weighs 345.8 g and is filled with 225 mL of carbon filled with 225 mL of carbon tetrachloride. The weight of the tetrachloride. The weight of the flask and carbon tetrachloride is flask and carbon tetrachloride is found to be 703.55 g. Calculate found to be 703.55 g. Calculate the density in g/ml and g/Lthe density in g/ml and g/L

DensityDensity

A 28.5 g of iron shot is added to a A 28.5 g of iron shot is added to a graduated cylinder containing graduated cylinder containing 45.5 mL of water. The water level 45.5 mL of water. The water level rises to the 49.1 mL mark. rises to the 49.1 mL mark. Calculate the density.Calculate the density.

DensityDensity

A cylindrical tube of length 27.75 A cylindrical tube of length 27.75 cm and radius of 2.00 cm is filled cm and radius of 2.00 cm is filled with argon gas. The empty tube with argon gas. The empty tube weighs 188.25g. The tube filled weighs 188.25g. The tube filled with argon weighs 188.87g . with argon weighs 188.87g . Calculate the density. Calculate the density.

AssignmentAssignment

Complete the section review on Complete the section review on page 42 and do numbers 1-5.page 42 and do numbers 1-5.

This is due tomorrow!This is due tomorrow!