Describing MatterDescribing Matter

1.21.2

ObjectiveObjective/Warm-Up/Warm-Up

The students will be able to use the metric system to solve conversion problems and solve density problems.

What do you know about the What do you know about the metric system? Why is it useful?metric system? Why is it useful?

Chemistry investigates Chemistry investigates the nature of matterthe nature of matter

MatterMatter – anything that has – anything that has mass and takes up spacemass and takes up space

VolumeVolume – a measure of the – a measure of the size of a body or region in 3 size of a body or region in 3 dimensional spacedimensional space

How do you measure the How do you measure the volume of…volume of…

Mass vs. WeightMass vs. Weight

MassMass – the measure of the – the measure of the amount of matter in an objectamount of matter in an object–Measured with what?Measured with what?

WeightWeight – a measure of the – a measure of the gravitational force exerted on an gravitational force exerted on an objectobject

What’s the difference?What’s the difference?

Units of MeasurementUnits of Measurement

Qualitative description – Qualitative description – describes qualities/appearance describes qualities/appearance ex: large, small, texture, colorex: large, small, texture, color

Quantative description – Quantative description – describes numbers describes numbers ex: 15 grams, 125 ex: 15 grams, 125 poundspounds

QuantityQuantity – something that has – something that has magnitude or sizemagnitude or size

Units of MeasureUnits of Measure

UnitUnit – a standard used when – a standard used when measuring a quantity measuring a quantity ex: 15 grams (grams is ex: 15 grams (grams is the unit)the unit)

Every numerical Every numerical measurement must have a measurement must have a quantity and a unit!!!quantity and a unit!!!

SI UnitsSI Units

MeasuremeMeasurementnt

QuantitQuantityy

UnitUnit

15 kilograms15 kilograms 1515 kilogramskilograms

30 30 millimetersmillimeters

3030 millimetemillimetersrs

The Measurement System of The Measurement System of

ScienceScience Do these mean Do these mean

anything to you?anything to you? Kilo:Kilo:

– kilometer, kilogramkilometer, kilogram Centi:Centi:

– centimeter, cents, centimeter, cents, centurycentury

DecaDeca– Decathlon, decadeDecathlon, decade

SI UnitsSI UnitsScientists use a system Scientists use a system

called the SI Systemcalled the SI System–Allows for universal Allows for universal measurementsmeasurements

–Enables you to use more Enables you to use more manageable numbersmanageable numbers

SI units chart and SI SI units chart and SI prefixes chartprefixes chart

SI Prefixes!SI Prefixes!Unit Symbol Meaning

Mega M 1M(b.u.) = 1,000,000 (b.u.)

Kilo k 1k(b.u.) = 1,000 (b.u.)

Hecto h 1h(b.u.) = 100 (b.u.)

Deca da 1da(b.u.) = 10 (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.)

So what? How do we So what? How do we use them?use them?

Any SI unit has two Any SI unit has two parts:parts:– prefixprefix– basebase

For example,For example,– kilokilo--gramgram– kilokilo--metemeterr– centicenti--metermeter– centicenti--gramgram

So, what do we So, what do we call 10 grams?call 10 grams?– decadeca--gramgram

What do we What do we call .001 seconds?call .001 seconds?– millimilli--secondsecond

How about .1 How about .1 liters?liters?– decideci--literliter

Conversion FactorsConversion Factors

Conversion FactorConversion Factor – a – a mathematical expression that mathematical expression that relates two units relates two units

Quarters and dollars Quarters and dollars conversion factor – 4 quarters conversion factor – 4 quarters = 1 dollar= 1 dollar

Convert 18 quarters to dollarsConvert 18 quarters to dollars

ConversionsConversions

Start with what you knowStart with what you know What you are going to goes What you are going to goes

in the top and coming from in the top and coming from goes in the bottomgoes in the bottom

Convert 3 dollars to Convert 3 dollars to quartersquarters

ConversionsConversions

Convert 45 minutes to Convert 45 minutes to hours.hours.

0.75 hours0.75 hoursConvert 2.5 hours to Convert 2.5 hours to

minutes.minutes.150 minutes150 minutes

ConversionsConversions

Convert 100 millimeters to Convert 100 millimeters to metersmeters

1 meter = 1000millimeters1 meter = 1000millimeters0.1m0.1mConvert 3 hours to secondsConvert 3 hours to seconds10,800 seconds10,800 seconds

ConversionsConversions

Convert 0.12 kg to mgConvert 0.12 kg to mgMust convert to base unit Must convert to base unit

first if going from one side first if going from one side to the other.to the other.

Convert 130 cm to MmConvert 130 cm to Mm

Derived Units

When 7 main don’t cover itSpeed = distance over time or meters/second

Rectangle = l x w = m2

Common for chemistry is 1 L = 1000 mL = 1000 cm3

Properties of MatterProperties of Matter

Physical PropertyPhysical Property – a – a characteristic of a substance characteristic of a substance that does not involve a chemical that does not involve a chemical change - ex: density, color, change - ex: density, color, melting point, b.p., texturemelting point, b.p., texture

Also can be seen by the absence Also can be seen by the absence of something like colorof something like color– it’s colorlessit’s colorless

Properties of MatterProperties of Matter

Chemical PropertyChemical Property – a property – a property of matter that describes a of matter that describes a substances ability to participate substances ability to participate in chemical rxns in chemical rxns

ex: iron rusts in the presence of ex: iron rusts in the presence of oxygen, acids react with bases oxygen, acids react with bases to form saltsto form salts

Specific Physical Specific Physical PropertyProperty DensityDensity – the ratio of mass to – the ratio of mass to

volume D=m/vvolume D=m/v Usually expressed as g/cmUsually expressed as g/cm33

for solids and g/L for gasesfor solids and g/L for gases Does not depend on how Does not depend on how

much of the substance you much of the substance you havehave

DensityDensity

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

displaces water, volume is displaces water, volume is 20.5 cm20.5 cm33

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 A piece of an unknown material has a mass of material has a mass of 5.85 g and a volume of 5.85 g and a volume of 7.57 cm7.57 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 A 200 g piece of metal has a volume of 25 cmvolume of 25 cm33. Calculate . Calculate the density of the metal.the density of the metal.

An unknown mass of silicon An unknown mass of silicon occupies a volume of 350 occupies a volume of 350 cmcm33. Calculate the mass of . Calculate the mass of Si knowing that the density Si knowing that the density of Si is 2.34 g/cmof Si is 2.34 g/cm33..

DensityDensity

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

AssignmentAssignment

Complete Section Complete Section Review on page 19 Review on page 19 numbers 1-12.numbers 1-12.

This is due tomorrow.This is due tomorrow.