Units of Measurements - Belle Vernon Area School District
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Transcript Units of Measurements - Belle Vernon Area School District
Units of Measurement
2.2
Definitions
Weight –measure of the gravitational
pull on matter
Diff between mass and weight
Quantity – something that has
magnitude, size or amount
Every measurement must have a unit
SI-Le Système International d’Unitès
We use 7 base units and prefixes to
express all units
Quantity
Length
Symbol Unit
l
Meter
Abbreviation
m
Mass
m
Kilogram kg
Time
t
Second
s
Thermodynamic
Temperature
Amount of a
Substance
Electric Current
Luminous
Velocity
T
Kelvin
k
n
Mole
mol
I
Iυ
Ampere
Candela
A
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 Units
Combination of SI base units
Examples – m3, g/cm3, kg/mol
Volume – the amount of space
occupied by an object
1000mL = 1 L = 1000cm3
Conversion Factors
Ratio derived from the equality b/t 2
different units that can be used to
convert from 1 unit to another
Ex: there are 4 quarters in 1 dollar
Dimensional analysis – math
technique that allows you to use
units to solve problems involving
measurments
Conversion Factors
Quarters and dollars conversion
factor – 4 quarters = 1 dollar
Convert 18 quarters to dollars
Start with what you know
What you are going to goes in the
top and coming from goes in the
bottom
Convert 3 dollars to quarters
Conversions
Convert 45 minutes to hours.
Convert 2.5 hours to minutes.
Convert 100 millimeters to
meters
1 meter = 1000millimeters
Convert 3 hours to seconds
Conversions
Convert 0.12 kg to mg
Must convert to base unit first if
going from one side to the other.
Convert 130 cm to Mm
Conversions with Derived Units
Convert 60 miles/hour to
kilometers per second
1 mile = 1.609 kilometers
How many grams per milliliter are
there in 34 kilograms per liter
Density
The ratio of mass to volume
D = m
Know this
v
equation!!!
Typically expressed as g/cm3.
Predict the order of the following from
the most dense to the lease dense…
Milk, mercury, gasoline, ice, a
diamond, a cork
Density
Silver Bracelet
Mass is 100.0 g and when it
displaces water, volume is 20.5
cm3
Density of silver is 10.5 g/cm3
Is this a silver bracelet?
Density Calculations
A piece of an unknown material
has a mass of 5.85 g and a
volume of 7.57 cm3. What is the
density of the material?
Density Calculations
D = m
v
D = m = 5.85 g
v
7.57 cm3
Density = 0.77 g/cm3
Density calculations
A 200 g piece of metal has a volume
of 25 cm3. Calculate the density of
the metal.
An unknown mass of silicon
occupies a volume of 350 cm3.
Calculate the mass of Si knowing
that the density of Si is 2.34 g/cm3.
Density
What is the volume that a 50
gram piece of gold occupies?
The density of gold is
19.30g/cm3.
Density
A block of lead with dimensions of
2.0dm x 8.0cm x 35mm, has a
mass of 6.356kg. Calculate the
density of lead in g/cm3.
Density
A flask weighs 345.8 g and is
filled with 225 mL of carbon
tetrachloride. The weight of the
flask and carbon tetrachloride is
found to be 703.55 g. Calculate
the density in g/ml and g/L
Density
A 28.5 g of iron shot is added to a
graduated cylinder containing
45.5 mL of water. The water level
rises to the 49.1 mL mark.
Calculate the density.
Density
A cylindrical tube of length 27.75
cm and radius of 2.00 cm is filled
with argon gas. The empty tube
weighs 188.25g. The tube filled
with argon weighs 188.87g .
Calculate the density.
Assignment
Complete the section review on
page 42 and do numbers 1-5.
This is due tomorrow!