Introductory Chemistry, 2 nd Edition Nivaldo Tro Chapter 3 Matter and Energy.

Introductory ChemistryIntroductory Chemistry, 2, 2ndnd Edition EditionNivaldo TroNivaldo Tro

Chapter 3Matter and Energy

Tro's Introductory Chemistry, Chapter 3Tro's Introductory Chemistry, Chapter 3 22

In Your RoomIn Your Room

Everything you can Everything you can see, touch, smell or see, touch, smell or taste in your room is taste in your room is made of made of mattermatter..

Chemists study the Chemists study the differences in matter differences in matter and how that relates to and how that relates to the structure of matter. the structure of matter.


What is Matter?What is Matter?

MatterMatter is anything that is anything that occupies space and has occupies space and has massmassEven though it appears Even though it appears to be smooth and to be smooth and continuous, matter is continuous, matter is actually composed of a actually composed of a lot of tiny particles called lot of tiny particles called atomsatoms and and moleculesmolecules


Atoms and MoleculesAtoms and Molecules

AtomsAtoms are the tiny are the tiny particles that make up particles that make up all matter.all matter.

In most substances, the In most substances, the atoms are joined atoms are joined together in units called together in units called moleculesmolecules


Classifying Matter by Physical StateClassifying Matter by Physical State

Matter can be classified as Matter can be classified as solid, liquid or solid, liquid or gasgas based on what properties it exhibits based on what properties it exhibits

State Shape Volume Compress Flow

Solid Fixed Fixed No No

Liquid Indef. Fixed No Yes

Gas Indef. Indef. Yes Yes

• Fixed = keeps shape when placed in a container, Fixed = keeps shape when placed in a container, • Indefinite = takes the shape of the containerIndefinite = takes the shape of the container

66

Structure Determines PropertiesStructure Determines Properties

The atoms or molecules have different The atoms or molecules have different structures in solids, liquid and gases, structures in solids, liquid and gases, leading to different propertiesleading to different properties


SolidsSolids

Particles in solid are packed close Particles in solid are packed close together and are fixed in positiontogether and are fixed in position– though they may vibratethough they may vibrate

Close packing of particles results Close packing of particles results in solids being incompressiblein solids being incompressible

Inability of particles to move Inability of particles to move around results in solids retaining around results in solids retaining shape and volume when placed in shape and volume when placed in a new container and prevents a new container and prevents flow of particles.flow of particles.


SolidsSolids

Some solids have their Some solids have their particles arranged in an orderly particles arranged in an orderly geometric pattern – we call geometric pattern – we call these these crystalline solidscrystalline solids– salt and diamondssalt and diamondsOther solids have particles that Other solids have particles that do not show a regular do not show a regular geometric pattern over a long geometric pattern over a long range – we call these range – we call these amorphous solidsamorphous solids– plastic and glassplastic and glass


LiquidsLiquids

Particles in a liquid are closely Particles in a liquid are closely packed, but they have some ability packed, but they have some ability to move around to move around

Close packing results in liquids Close packing results in liquids being incompressiblebeing incompressible

Ability of particles to move allows Ability of particles to move allows liquids to take the shape of their liquids to take the shape of their container and to flow – however container and to flow – however they don’t have enough freedom to they don’t have enough freedom to escape and expand to fill the escape and expand to fill the containercontainer


GasesGases

Particles in gases have Particles in gases have complete freedom of motion complete freedom of motion from each otherfrom each other

Particles are constantly flying Particles are constantly flying around, bumping into each around, bumping into each other and the containerother and the container

In gas state, there is a lot of In gas state, there is a lot of empty space between the empty space between the particlesparticles– on average on average


GasesGases

Because there is a lot of Because there is a lot of empty space, the particles empty space, the particles can be squeezed closer can be squeezed closer together – therefore together – therefore gases gases are compressibleare compressible

Because the particles are Because the particles are not held in close contact not held in close contact and are moving freely, and are moving freely, gases expand to fill and gases expand to fill and take the shape of their take the shape of their container, and will flowcontainer, and will flow


Classifying Matter by CompositionClassifying Matter by Composition

Matter composed of only one kind of particle Matter composed of only one kind of particle is a is a pure substancepure substance

Matter composed of different kinds of Matter composed of different kinds of particles is a particles is a mixturemixture

Because Because pure substancespure substances always have only always have only one kind of particle, all samples show the one kind of particle, all samples show the same propertiessame properties

Because Because mixturesmixtures have variable composition, have variable composition, different samples will show different samples will show different different propertiesproperties


Copper – a Pure SubstanceCopper – a Pure Substance

color – brownish redcolor – brownish red

shiny, malleable and ductileshiny, malleable and ductile

excellent conductor of heat and excellent conductor of heat and electricityelectricity

melting point = 1084.62°Cmelting point = 1084.62°C

density = 8.96 g/cmdensity = 8.96 g/cm33 at 20°C at 20°C


Brass – a MixtureBrass – a MixtureTypeType ColorColor % %

CuCu% Zn% Zn DensityDensity

g/cmg/cm33

MPMP

°C°C

UsesUses

GildingGilding reddishreddish 9595 55 8.868.86 10661066 pre-83 pennies,pre-83 pennies,munitions, munitions,

plaquesplaques

CommercialCommercial bronzebronze 9090 1010 8.808.80 10431043 door knobs,door knobs,grillworkgrillwork

JewelryJewelry bronzebronze 87.587.5 12.512.5 8.788.78 10351035 costume jewelrycostume jewelry

RedRed goldengolden 8585 1515 8.758.75 10271027 electrical electrical sockets,sockets,

fasteners & fasteners & eyeletseyelets

CommonCommon yellowyellow 6767 3333 8.428.42 940940 lamp fixtures,lamp fixtures,bead chainbead chain

Muntz metalMuntz metal yellowyellow 6060 4040 8.398.39 904904 nuts & bolts,nuts & bolts,


Classification of MatterClassification of Matter

Pure SubstancePure Substance = all samples are made of the same = all samples are made of the same particles in the same percentagesparticles in the same percentages– saltsalt

Mixtures Mixtures = different samples may have the same = different samples may have the same particles in different percentagesparticles in different percentages– salt watersalt water

Pure SubstanceConstant Composition

Homogeneous

MixtureVariable Composition

Matter


Classification of MixturesClassification of Mixtures

homogeneoushomogeneous = matter that is uniform throughout = matter that is uniform throughout

– appears to be one thingappears to be one thing

– also called also called solutionssolutions (homogeneous mixtures) (homogeneous mixtures)

heterogeneousheterogeneous = matter that is non-uniform = matter that is non-uniform throughout throughout

– contains regions with different properties than contains regions with different properties than other regionsother regions

1717

Pure Substances vs. MixturesPure Substances vs. MixturesPure SubstancesPure Substances

1)1) samples have same samples have same physical and chemical physical and chemical propertiesproperties

2)2) constant composition; constant composition; homogeneoushomogeneous

3)3) separate into separate into components based on components based on chemical propertieschemical properties

4)4) temperature usually temperature usually stays constant while stays constant while melting or boilingmelting or boiling

MixturesMixtures

1)1) variable composition, variable composition, samples have different samples have different physical and chemical physical and chemical properties.properties.

2)2) homogeneous or homogeneous or heterogeneousheterogeneous

3)3) separate into separate into components based on components based on physical propertiesphysical properties

4)4) temperature changes temperature changes while melting or boiling while melting or boiling because composition because composition changeschanges


Classifying Pure SubstancesClassifying Pure SubstancesElements and CompoundsElements and Compounds

ElementsElements = substances which can not be = substances which can not be broken down into simpler substances by broken down into simpler substances by chemical reactions; can be atoms or chemical reactions; can be atoms or moleculesmolecules

CompoundsCompounds = chemical combinations of = chemical combinations of elements elements – compounds can be broken down into compounds can be broken down into

elementselements– properties of compound not related to properties of compound not related to

properties of elements that compose itproperties of elements that compose it


Know these Element Symbols:

Al BrBr CaCaC ClCl CuFF HH IIFe PbPb LiLiMg N OP KK AgAgNaNa S Zn

aluminum

carbon

fluorinefluorine

iron

magnesium

phosphorus

sodium

brominebromine

chlorinechlorine

hydrogenhydrogen

leadlead

nitrogen

potassiumpotassium

sulfursulfur

calcium

copper

iodineiodine

lithium

oxygen

silversilver

zinc


Atoms & MoleculesAtoms & Molecules

AtomAtom = = smallest particle of an smallest particle of an elementelement that retains its properties that retains its properties

MoleculeMolecule = made up of 2 or more = made up of 2 or more atoms chemically bonded; smallest atoms chemically bonded; smallest particle of a compound particle of a compound – all molecules of a compound are all molecules of a compound are

identicalidentical– each molecule has the same number each molecule has the same number

and type of atomsand type of atoms


Classifying MatterClassifying Matter


ElementsElements

116 known, of which about 91 are found in 116 known, of which about 91 are found in nature (see Periodic Table)nature (see Periodic Table)– others are man-madeothers are man-made

Abundance = percentage found in natureAbundance = percentage found in nature– oxygen most abundant element (by mass) on oxygen most abundant element (by mass) on

earth and in the human bodyearth and in the human body

Abundance and form of an element varies Abundance and form of an element varies in different parts of the environmentin different parts of the environment

Every sample of an element is made up of Every sample of an element is made up of lots of identical atomslots of identical atoms


CompoundsCompoundsComposed of elements combined in fixed Composed of elements combined in fixed percentagespercentages– water is 89% O & 11% Hwater is 89% O & 11% H

Billions of known compoundsBillions of known compoundsOrganic or inorganicOrganic or inorganicSame elements can form more than one Same elements can form more than one different compounddifferent compound– water and hydrogen peroxide contain just water and hydrogen peroxide contain just

hydrogen and oxygenhydrogen and oxygen– carbohydrates all contain just C, H & Ocarbohydrates all contain just C, H & O


Element or Compound?

C

H2O

Fe

N2

CO2

NO

O2

element

elementelement

compound

compound

compound

element


Element or Compound?Atom or MoleculeMolecule?

C

H2O

Fe

N2

CO2

NO

O2

atom

atommoleculemolecule

molecule

moleculemolecule

moleculemolecule

moleculemolecule

element

elementelement

compound

compound

compound

element


Properties of MatterProperties of Matter

Physical PropertiesPhysical Properties = characteristics of = characteristics of matter that can be changed without matter that can be changed without changing its compositionchanging its composition– characteristics that are directly observablecharacteristics that are directly observable

Chemical PropertiesChemical Properties = characteristics = characteristics that determine how the composition of that determine how the composition of matter changes as a result of contact matter changes as a result of contact with other matter or the influence of with other matter or the influence of energy energy – characteristics that describe the behavior of characteristics that describe the behavior of

mattermatter


Some Physical PropertiesSome Physical Properties

mass volume density

solid liquid gas

melting point boiling point volatility

taste odor color

texture shape solubility

electrical conductance

thermal conductance

magnetism

malleability ductility specific heat capcity


Some Chemical PropertiesSome Chemical Properties

Acidity Basicity (aka Alkalinity)

Causticity Corrosiveness

Reactivity Stability

Inertness Explosiveness

(In)Flammability Combustibility

Oxidizing Ability Reducing Ability


Some Physical Properties of Some Physical Properties of IronIron

A silvery solid at room temperature with a A silvery solid at room temperature with a metallic taste and smooth texturemetallic taste and smooth texture

Melts at 1538°C and boils at 4428°CMelts at 1538°C and boils at 4428°C

Density is 7.87 g/cmDensity is 7.87 g/cm33

Can be magnetizedCan be magnetized

Conducts electricity, but not as well as most Conducts electricity, but not as well as most other common metalsother common metals


Some Chemical Properties of Some Chemical Properties of IronIron

Easily oxidized in moist Easily oxidized in moist air to form rustair to form rust

When iron is added to When iron is added to hydrochloric acid, it hydrochloric acid, it produces a solution of produces a solution of ferric chloride and ferric chloride and hydrogen gashydrogen gas

Iron is more reactive than Iron is more reactive than silver, but less reactive silver, but less reactive than magnesiumthan magnesium


Chemical or Physical Property?Chemical or Physical Property?

Boiling point of 100º CBoiling point of 100º C

RustsRusts

High densityHigh density

Red colorRed color

FlammableFlammable

Non-reactive (inert)Non-reactive (inert)

Conducts electricityConducts electricity


ChemicalChemical PhysicalPhysical

Boiling point of 100º CBoiling point of 100º C

RustsRusts

High densityHigh density

Red colorRed color

FlammableFlammable

Non-reactive (inert)Non-reactive (inert)

Conducts electricityConducts electricity


Changes in MatterChanges in Matter

Physical ChangesPhysical Changes - changes in the - changes in the properties of matter that do not properties of matter that do not affect its compositionaffect its composition– Heating waterHeating water

raises its temperature, but it is still raises its temperature, but it is still waterwater

– Evaporating butane from a lighterEvaporating butane from a lighter– Dissolving sugar in waterDissolving sugar in water

even though the sugar seems to even though the sugar seems to disappear, it can easily be disappear, it can easily be separated back into sugar and separated back into sugar and water by evaporationwater by evaporation


Changes in MatterChanges in Matter

Chemical ChangesChemical Changes = change = change in identity or compositionin identity or composition– a chemical reactiona chemical reaction– rusting is iron combining with rusting is iron combining with

oxygen to make iron(III) oxideoxygen to make iron(III) oxide– burning butane from a lighter burning butane from a lighter

changes it into carbon dioxide changes it into carbon dioxide and waterand water

– silver combines with sulfur in silver combines with sulfur in the air to make tarnishthe air to make tarnish


Is it a Physical or Chemical ChangIs it a Physical or Chemical Change?e?

Physical change results in a different form of Physical change results in a different form of the same substancethe same substance– the kinds of molecules don’t change the kinds of molecules don’t change

Chemical change results in one or more Chemical change results in one or more completely new substancescompletely new substances– the new substances have different molecules than the new substances have different molecules than

the original substancesthe original substances– you will observe different physical properties you will observe different physical properties

because the new substances have their own because the new substances have their own physical propertiesphysical properties


Phase Changes arePhase Changes arePhysical ChangesPhysical Changes

Boiling = liquid to gasBoiling = liquid to gas

Melting = solid to liquidMelting = solid to liquid

Subliming = solid to gasSubliming = solid to gas

Condensing = gas to liquidCondensing = gas to liquid

Freezing = liquid to solidFreezing = liquid to solid

Deposition = gas to solidDeposition = gas to solid

State changes require heating or cooling the State changes require heating or cooling the substancesubstance


Separation of MixturesSeparation of MixturesSeparate mixtures based on different Separate mixtures based on different physical properties of the componentsphysical properties of the components– Physical changePhysical change

Centrifugation &Centrifugation &

DecantingDecantingDensityDensity

EvaporationEvaporationVolatilityVolatility

ChromatographyChromatographyAdherence to a SurfaceAdherence to a Surface

FiltrationFiltrationState of Matter (solid/liquid/gas)State of Matter (solid/liquid/gas)

DistillationDistillationBoiling PointBoiling Point

TechniqueTechniqueDifferent Physical PropertyDifferent Physical Property

3838

DistillationDistillation


FiltrationFiltration


Law of Conservation of MassLaw of Conservation of Mass

Antoine Lavoisier:Antoine Lavoisier:““Matter is neither created Matter is neither created nor destroyed in a chemical nor destroyed in a chemical reaction”reaction”Total amount of matter Total amount of matter present present before and afterbefore and after a a chemical reactionchemical reaction is always is always the samethe sameTotal mass of all reactants is Total mass of all reactants is equal to total mass of all equal to total mass of all productsproducts


Conservation of MassConservation of Mass

Total amount of matter remains constant in a Total amount of matter remains constant in a chemical reactionchemical reaction

58 grams of butane burns in 208 grams of 58 grams of butane burns in 208 grams of oxygen to form 176 grams of carbon dioxide oxygen to form 176 grams of carbon dioxide and 90 grams of water.and 90 grams of water.

butane + oxygen butane + oxygen carbon dioxide + carbon dioxide + water water

58 grams + 208 grams 58 grams + 208 grams 176 grams + 90 176 grams + 90 grams grams

266 grams = 266 grams266 grams = 266 grams


EnergyEnergy

Energy is anything that has the Energy is anything that has the capacity to do workcapacity to do work

Even though Chemistry is the study of Even though Chemistry is the study of matter, matter is affected by energymatter, matter is affected by energy

– it can cause physical and/or chemical it can cause physical and/or chemical changes in matterchanges in matter


Law of Conservation of EnergyLaw of Conservation of Energy

““Energy can neither be created nor Energy can neither be created nor destroyed”destroyed”

However we can transfer energy from However we can transfer energy from one place in the universe to another, one place in the universe to another, and we can change its form and we can change its form


Matter Possesses EnergyMatter Possesses Energy

When a piece of matter possesses When a piece of matter possesses energy, it can give some or all of it to energy, it can give some or all of it to another objectanother object

All chemical and physical changes All chemical and physical changes result in changing energyresult in changing energy


Kinds of EnergyKinds of EnergyKinetic and PotentialKinetic and Potential

Kinetic EnergyKinetic Energy is is energy of motion, or energy of motion, or energy that is being energy that is being transferred from one transferred from one object to anotherobject to another

Potential EnergyPotential Energy is is energy that is storedenergy that is stored


Some Forms of EnergySome Forms of Energy

Electrical: kinetic energy associated with flow Electrical: kinetic energy associated with flow of electrical chargeof electrical chargeHeat or Thermal Energy: kinetic energy Heat or Thermal Energy: kinetic energy associated with molecular motionassociated with molecular motionLight or Radiant Energy: kinetic energy Light or Radiant Energy: kinetic energy associated with energy transitions in an atomassociated with energy transitions in an atomNuclear: potential energy in the nuclei of Nuclear: potential energy in the nuclei of atoms atoms Chemical: potential energy in the attachment Chemical: potential energy in the attachment of atoms (chemical bonds) or because of their of atoms (chemical bonds) or because of their positionposition


Units of EnergyUnits of Energy

calorie (cal)calorie (cal) is the amount of energy is the amount of energy needed to raise one gram of water by 1°Cneeded to raise one gram of water by 1°C– kcal = energy needed to raise 1000 g of kcal = energy needed to raise 1000 g of

water 1°Cwater 1°C– food Calories = kcalsfood Calories = kcals

Energy Conversion FactorsEnergy Conversion Factors

1 calorie (cal)1 calorie (cal) == 4.184 joules (J)4.184 joules (J)

1 Calorie (Cal)1 Calorie (Cal) == 1000 calories (cal)1000 calories (cal)


The Meaning of HeatThe Meaning of Heat

Heat is the exchange of thermal Heat is the exchange of thermal energyenergy between samples of matterbetween samples of matter

Heat flows from matter that has high Heat flows from matter that has high thermal energy to matter that has low thermal energy to matter that has low thermal energythermal energy

– until they reach the same temperatureuntil they reach the same temperature

heat is exchanged through molecular heat is exchanged through molecular collisions between two samplescollisions between two samples


The Meaning of TemperatureThe Meaning of Temperature

Temperature is a Temperature is a measuremeasure of the average of the average kinetic energy of the molecules in a kinetic energy of the molecules in a samplesample

Not all molecules in a sample have the Not all molecules in a sample have the same kinetic energysame kinetic energy

Higher temperature means larger Higher temperature means larger average kinetic energyaverage kinetic energy

Prentice HallPrentice Hall 5050

Temperature Scales Temperature Scales


Fahrenheit Temperature ScaleFahrenheit Temperature Scale

The Fahrenheit Temperature Scale The Fahrenheit Temperature Scale used as its two reference points the used as its two reference points the freezing point of concentrated saltwater freezing point of concentrated saltwater (0°F) and average body temperature (0°F) and average body temperature (100°F)(100°F)– more accurate measure now set average more accurate measure now set average

body temperature at 98.6°Fbody temperature at 98.6°F

Room temperature is about 75°F Room temperature is about 75°F


Celsius Temperature ScaleCelsius Temperature Scale

The Celsius Temperature Scale used The Celsius Temperature Scale used as its two reference points the freezing as its two reference points the freezing point of distilled water (0°C) and point of distilled water (0°C) and boiling point of distilled water (100°C)boiling point of distilled water (100°C)

– more reproducible standardsmore reproducible standards

– most commonly used in sciencemost commonly used in science

Room temperature is about 25°C Room temperature is about 25°C


Fahrenheit vs. CelsiusFahrenheit vs. Celsius

A Celsius degree is 1.8 times larger A Celsius degree is 1.8 times larger than a Fahrenheit degreethan a Fahrenheit degree

The standard used for 0° on the The standard used for 0° on the Fahrenheit scale is a lower Fahrenheit scale is a lower temperature than the standard used temperature than the standard used for 0° on the Celsius scalefor 0° on the Celsius scale

1.8

32-F C


The Kelvin Temperature ScaleThe Kelvin Temperature Scale

The Kelvin scale is an absolute scale, The Kelvin scale is an absolute scale, meaning it measures the actual meaning it measures the actual temperature of an object temperature of an object

0 K is called Absolute Zero0 K is called Absolute Zero. It is too cold . It is too cold for matter to exist at because all molecular for matter to exist at because all molecular motion would stopmotion would stop

– 0 K = -273°C = - 459°F0 K = -273°C = - 459°F

– Absolute Zero is a theoretical value obtained Absolute Zero is a theoretical value obtained by following patterns mathematicallyby following patterns mathematically


Kelvin vs. CelsiusKelvin vs. Celsius

The size of a “degree” on the Kelvin The size of a “degree” on the Kelvin scale is the same as on the Celsius scale is the same as on the Celsius scalescale– though technically, we don’t call the though technically, we don’t call the

divisions on the Kelvin scale degrees; we divisions on the Kelvin scale degrees; we called them kelvins!called them kelvins!

– that makes 1 K 1.8 times larger than 1°Fthat makes 1 K 1.8 times larger than 1°FThe 0 standard on the Kelvin scale is a much The 0 standard on the Kelvin scale is a much lower temperature than on the Celsius scalelower temperature than on the Celsius scale

273C K

Example 3.8:Example 3.8:Converting BetweenConverting Between

Fahrenheit and KelvinFahrenheit and KelvinTemperature ScalesTemperature Scales


Example:Example:

Convert 310 K to FahrenheitConvert 310 K to Fahrenheit


Example:Example:Convert 310 K to FahrenheitConvert 310 K to Fahrenheit

Write down the given quantity and its units. Write down the given quantity and its units.

Given:Given: 310 K 310 K


Write down the quantity to find and/or its units.Write down the quantity to find and/or its units.

Find: Find: ? °F? °F

InformationInformation

Given:Given: 310 K310 K



Collect Needed Equations:Collect Needed Equations:


Given:Given: 310 K310 K

Find:Find: ? °F? °F


1.8

32-F C

273C K


Write a Solution Map:Write a Solution Map:


Given: 310 KGiven: 310 K


Eq’ns: Eq’ns:

KK °C°C °F°F


1.8

32-F C

273C K

1.8

32-F C

273C K

C 273K 32-F C81 .

F 23C1.8


Apply the Solution Map:Apply the Solution Map:

= 99°F • Sig. Figs. & Round:




Eq’ns:Eq’ns:

Sol’n Map:Sol’n Map: K K °C °C °F °F


C 273K

F 23C1.8 C 273K

F 23C1.8

C 273103 C 37

F 23371.8 F 8.69


Check the Solution:Check the Solution:

310 K = 99 °F

The units of the answer, °F, are correct.The magnitude of the answer makes sense

since both are above, but close to, Room Temperature.




Eq’ns:Eq’ns:

Sol’n Map:Sol’n Map: K K °C °C °F °F


C 273K F 23C1.8

Introductory Chemistry, 2 nd Edition Nivaldo Tro Chapter 3 Matter and Energy.

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Transcript of Introductory Chemistry, 2 nd Edition Nivaldo Tro Chapter 3 Matter and Energy.