55

You can do it.You can do it.

Chapter 1Chapter 1Matter and Matter and

MeasurementMeasurement

States of MatterStates of Matter

SolidSolid

–

LiquidLiquid

–

GasGas

–

PlasmaPlasma

Matter

Pure substances (homogeneous composition)

Mixtures of two or more substances

Elements Compounds

Solutions (homogeneous

composition – one phase)

Heterogeneous mixtures

(two or more phases)

Figure 3.2 (page 48)

Classifying SubstancesClassifying Substances

MixturesMixtures

HomogeneousHomogeneous– – –

HeterogeneousHeterogeneous– – –

Pure substancePure substance

A particular kind of matter with a definite, A particular kind of matter with a definite, fixed compositionfixed composition– Elements Elements – Compounds Compounds

CompoundsCompounds

Two or more elements Two or more elements

New New

Definite Definite

Can be Can be

How would you classify?How would you classify?

GatoradeGatorade

Caesar saladCaesar salad

WaterWater

CoffeeCoffee

An iron nailAn iron nail

AirAir

MilkMilk

Methods of SeparationMethods of Separation

Do not cause chemical changesDo not cause chemical changes

FiltrationFiltration

Used for Used for

GravityGravity

VacuumVacuum

SublimationSublimation

EvaporationEvaporation

SolutionsSolutions……

DistillationDistillation

Relies on Relies on

ChromatographyChromatography

Relies on Relies on

DecantationDecantation

CrystallizationCrystallization

55

The Metric SystemThe Metric SystemThe International System of UnitsThe International System of Units

Standards of measurementStandards of measurementBase units (7) – see Table 1.4 pg 14Base units (7) – see Table 1.4 pg 14

1.1. MASS: MASS: 2.2. LENGTH: LENGTH: 3.3. TIME: TIME: 4.4. COUNT, QUANTITY: COUNT, QUANTITY: 5.5. TEMPERATURE: TEMPERATURE: 6.6. ELECTRIC CURRENT: ELECTRIC CURRENT: 7.7. LUMINOUS INSTENSITY: LUMINOUS INSTENSITY:

The Metric SystemThe Metric SystemDerived Units:Derived Units: AREA: AREA: VOLUME: VOLUME: ENERGY: ENERGY: FORCE: FORCE: PRESSURE:PRESSURE: POWER: POWER: VOLTAGE: VOLTAGE: FREQUENCY: FREQUENCY: ELECTRIC CHARGE: ELECTRIC CHARGE:

DensityDensityCommon ratio used in Common ratio used in chemistrychemistry

Physical property of a Physical property of a substancesubstance

D = D =

SI units: kg/mSI units: kg/m33

SolidSolid– g/cmg/cm33

LiquidLiquid– g/mLg/mL

GasGas– g/Lg/L

Can change due to temperature and/or pressure changes

DensityDensity

1.Find the density of a piece of metal with a volume of 2.7 cm3 and a mass of 10.8 g.

2. Determine the mass of an object with a density of 0.24 g/cm3 and a volume of 2 cm3.

The Metric SystemThe Metric System

Metric Prefixes – make base unit larger Metric Prefixes – make base unit larger or smalleror smaller

Table 1.5 – pg 14Table 1.5 – pg 14

Based on 10Based on 10

Math method vs. “Stairs”Math method vs. “Stairs”

Convert a volume of 12 microliters into Convert a volume of 12 microliters into centiliterscentiliters

Express a distance of 15 meters in Express a distance of 15 meters in kilometerskilometers

Convert 83 cm into metersConvert 83 cm into meters

Which is the longer amount of time, 1351 Which is the longer amount of time, 1351 ps or 1.2 ns?ps or 1.2 ns?

Convert 16 dL into LConvert 16 dL into L

Conversion PracticeConversion Practice

Uncertainty in MeasurementUncertainty in Measurement

Why are digits in measurements uncertain?Why are digits in measurements uncertain?

1.1. Instruments never completely free of flawsInstruments never completely free of flaws

2.2. Always involves estimationAlways involves estimation Choose the right instrument for the jobChoose the right instrument for the job May be estimated for you (electronic May be estimated for you (electronic

scales)scales) Scale is marked but you estimate the in-Scale is marked but you estimate the in-

betweenbetween

Uncertainty in MeasurementUncertainty in Measurement

Precision: getting the same result again Precision: getting the same result again and again under same conditionsand again under same conditions

Accuracy: close to accepted valueAccuracy: close to accepted value

Significant DigitsSignificant DigitsAll digits known with certainty plus one All digits known with certainty plus one final digit which is uncertain (or estimated)final digit which is uncertain (or estimated)

All non-zeros All non-zeros

A zero is significant when :A zero is significant when :– It is It is – It is It is

A zero is not significant when:A zero is not significant when:– It is It is – It is It is

Significant Digits - PRACTICESignificant Digits - PRACTICE

How many significant digits?How many significant digits?1.1. 54.2354.232.2. 23.0000523.000053.3. 0.00040.00044.4. 35000350005.5. 0.0005040.0005046.6. 45.62320045.6232007.7. 5,000,0005,000,0008.8. 4,000,000.14,000,000.1

Significant Digits - CalculationsSignificant Digits - Calculations

Addition and SubtractionAddition and Subtraction– Round answer to have final digit in the SAME Round answer to have final digit in the SAME

PLACE as the last digit in the LEAST PLACE as the last digit in the LEAST ACCURATE MEASUREMENTACCURATE MEASUREMENT

1.21 + 5.002 + 10. = 1.21 + 5.002 + 10. = 34.5 + 12.45 + 23.0505 = 34.5 + 12.45 + 23.0505 = 186.31 + 11.1 = 186.31 + 11.1 = 12.0231 + 3.86 = 12.0231 + 3.86 = 0.100012 + 120. =0.100012 + 120. = 1200 + 12 + 15 + 0.5 =1200 + 12 + 15 + 0.5 =

Significant Digits - CalculationsSignificant Digits - Calculations

Multiplication and DivisionMultiplication and Division– The answer has as many sig figs as the The answer has as many sig figs as the

number with the fewest sig figsnumber with the fewest sig figs14.8 x 3.1 = 14.8 x 3.1 =

18.2 x 3.0 =18.2 x 3.0 =

52/1.5 =52/1.5 =

321.868783 x 1 =321.868783 x 1 =

2400 x 2.123 =2400 x 2.123 =

15000/12.354 =15000/12.354 =

Scientific NotationScientific Notation

Convenient way of writing very large or Convenient way of writing very large or very small numbers and showing only very small numbers and showing only significant figuressignificant figuresNumber between 1 & 10 with a power of Number between 1 & 10 with a power of tenten5120 becomes 5.12 x 105120 becomes 5.12 x 1033

Move decimal point in original number to Move decimal point in original number to make number 1-10make number 1-10Move left = +; move right = -Move left = +; move right = -

Scientific Notation PracticeScientific Notation Practice

123,000 =123,000 =

0.000045 =0.000045 =

23.45 =23.45 =

0.0000000003 =0.0000000003 =

1,000,000 =1,000,000 =

Scientific NotationScientific Notation

Math with:Math with:

– Use the EE or EXP button on your Use the EE or EXP button on your calculator.calculator.

– For example:For example:(1.25 x 10(1.25 x 1055) (5.25 x 10) (5.25 x 1022))

Keystrokes are: Keystrokes are:

Or: Or:

Types of MeasurementsTypes of Measurements

Mass – Mass – – Expressed in Expressed in – Does Does

Weight – Weight – – Expressed in same unitsExpressed in same units–

Types of MeasurementsTypes of Measurements

Volume – Volume – – Cubic Cubic – Many instruments to measureMany instruments to measure

Temperature – Temperature – – KelvinKelvin– Degrees CelsiusDegrees Celsius– Degress FarenheitDegress Farenheit

Conversion FactorsConversion Factors

Enable movement between metric system and Enable movement between metric system and “English” system“English” system

See back cover of book and Appendix IIISee back cover of book and Appendix III

Common conversions you should memorizeCommon conversions you should memorize– 1 inch = 2.54 cm1 inch = 2.54 cm– 1 mile = 1.609 km1 mile = 1.609 km– 1 kg = 2.20 pounds1 kg = 2.20 pounds– 1 mL = 1 cm1 mL = 1 cm33

– 0 K = -273.15 0 K = -273.15 00CC– 00F = 1.8(F = 1.8(00C) + 32C) + 32

55

Dimensional AnalysisDimensional Analysis(Problem Solving)(Problem Solving)

Remember: ALWAYS use UNITS OF Remember: ALWAYS use UNITS OF MEASUREMENT in your work!!!MEASUREMENT in your work!!!

A technique of converting between unitsA technique of converting between units– Same system (metrics)Same system (metrics)– Different systems (inches to meters)Different systems (inches to meters)– Chemical equations….later chapters…Chemical equations….later chapters…

Dimensional AnalysisDimensional Analysis(Problem Solving)(Problem Solving)

Conversion Factors: ratio derived from the Conversion Factors: ratio derived from the equality between 2 different unitsequality between 2 different units

3 feet3 feet = 1 = 1 1 dollar 1 dollar = 1 = 1

1 yard1 yard 4 quarters4 quarters

CF can be written either wayCF can be written either way

1 minute 1 minute = 1= 1 60 seconds 60 seconds = 1 = 1

60 seconds60 seconds 1 minute 1 minute

Dimensional AnalysisDimensional Analysis(Problem Solving)(Problem Solving)

The “t” methodThe “t” method

unit given unit wanted = unit wanted

unit given

Example: How many liters are in 125.6 gallons?

Conversion Factor

How many seconds are in 4.15 hours?

Dimensional AnalysisDimensional Analysis(Problem Solving)(Problem Solving)

Dimensional AnalysisDimensional Analysis(Problem Solving)(Problem Solving)

If a student needs 1.5 mL of water, how many cups does he need?