Unit 1Unit 1

Structure of Matter

The Known UniverseThe Known Universe• Everything in the known universe can be

classified as either matter or energy.− Matter describes the physical things

around us: the earth, the air you breathe, your pencil.

− Energy is the ability to cause change or do work: including light, heat, electrical energy and mechanical energy, such as movement.

Matter & Its PropertiesMatter & Its Properties• The definition of matter has two parts

− All matter has volume, which is the 3-D space an object occupies

− All matter has mass, which is a measure of the amount of matter in an object.

Properties & Changes:

• There are 3 common states of matter− Solids have definite volume & definite shape

o Particles are limited in their movement and packed close together

− Liquids have definite volume but not definite shapeo Particles are able to move around each other yet are

still packed close together− Gases have neither definite vol. nor shape

o Particles are independent of each other

Properties & Changes:

• There are 2 other states of matter that are not as widely acknowledged− Plasma is the result of superheating gases− Supersolid or superfluid is the result of super-

cooling a solid (not much known about it so far, but lots of research possibilities)

Classification of Matter

• All forms of matter (no matter what it looks like) can be classified into one of two categories

Classification of Matter• Two categories:

− Pure substanceso Are uniform in compositiono Described by a chemical formula

− Mixtureso Are composed of more than one

component blended togethero Different substances physically mixed

together

Classification of Matter: Pure Substances

• A pure substance has a fixed composition− Every sample has exactly the same

characteristics.

− If they can be separated they can only be separated by chemical change (elements can not be broken down further)

− Can be identified by a unique chemical formula: H, Ar, C, H2O, CO2, CH4, C6H12O6

Classification of Matter: Pure SubstancesClassification of Matter: Pure Substances

MethanolCH4O

HexaneC6H14

CaffeineC8N4O2H10

Pure Substances: AtomsPure Substances: Atoms• Atoms are the most basic building blocks

of all matter.− There are 110+ different kinds of atomso All 110+ atoms look identical and are

composed of the same types of pieces called, subatomic particles

o However, an atom is mostly empty• There are 3 subatomic particles and they

differ in their location in the atom, their electrical charge and in their mass

Pure Substances: AtomsPure Substances: Atoms− In the center of the atom is an extremely

dense core called the nucleus, which is composed of protons and neutronso Protons are electrically positive, and make up

half of the mass of the atomo Neutrons are electrically neutral, and make

up the other half of the mass of the atom− Surrounding the nucleus is an electrically

negative “particle” called an electrono We tend to visualize the space the electrons occupy

as a negatively charged cloud

Classification of Matter: Pure Substances

− An element is a pure substance made up of only one type of atom

− Atoms can combine permanently together to make up moleculeso A molecule is the smallest version of

chemically combined atoms− Atoms combine to make up molecules,

atoms and/or molecules can combine to make up mixtures

Classification of Matter: MixturesClassification of Matter: Mixtures• Matter that isn’t pure must be a mixture

of pure substances− The components in a mixture are simply

blended together physically, which means they can be separated physically

− When pure substances are blended together the components have the same properties as when they are separateo Melting point, boiling point, density, resistance to

chemical change, etc.

Your Turn…Your Turn…• Classify each of the following as a mixture or

a pure substancePure substanceMixturePure substancePure substancePure substancePure substanceMixture Mixture Pure substancePure substanceMixture Mixture Mixture Mixture

WaterBloodTable saltTable saltIronIronBrassBrassUraniumUraniumWineWineLeatherLeather

Classification of Matter: Mixtures− There are 2 types of mixtures:o Heterogeneous mixtures

ando Homogeneous mixtures

Mixtures: Homogeneous MixturesMixtures: Homogeneous Mixtures• Homogeneous mixtures are uniform in

composition− They have the same proportion of

components throughout− This type of mixture is only composed of a

single phaseo Liquid, solid, gaseous, etc.

− AKA solutionso For example salt water, brass, air, etc. o Particle size at the ion, or molecule level, .1 –

2 nm.

Mixtures: Heterogeneous MixturesMixtures: Heterogeneous Mixtures• Heterogeneous mixtures are not uniform

− Often have more than one phaseo gas and liquid, gas and solid, solid and liquid. . .o e.g. Sea water, granite, blood, sand

Two categories:①A heterogeneous mixture of large (visible)

solid particles in a liquid is called a Suspensiono e.g. jar of muddy water, paint, dust particles in air.o Will settle over time.o Particle size greater than 1000 nm

Mixtures: Heterogeneous MixturesMixtures: Heterogeneous Mixtures

②A mixture of smaller particles that don’t settle out, but are still visible is called a Colloido e.g. Milk, smoke, fogo 2-1000 nm

Your Turn…Your Turn…• Classify each of the following as a Classify each of the following as a

homogeneous or heterogeneoushomogeneous or heterogeneousheterogeneousheterogeneousheterogeneousheterogeneousheterogeneousheterogeneoushomogeneoushomogeneoushomogeneous homogeneous homogeneoushomogeneous

SoilThe atmosphereA carbonated soft drinkGasolineGoldA solution of ethanol and water

Mixtures: Separation TechniquesMixtures: Separation Techniques• All mixtures can be separated by some kind

of physical method− Mixtures can be separated using several

techniques which have been developed based on the type of mixtureo Filtrationo Distillationo Chromatographyo Crystallization

Separation Techniques: ChromatographySeparation Techniques: Chromatography

• Chromatography is a technique that works for separating dissolved solids or a mixture of several liquids or even gaseous mixtures− Chromatography makes use of 2 phases to

separate the mixtureo Stationary phase – the phase the mixture is drawn

across, it attracts each component in the mobile phase differently

o Mobile phase – this phase contains the mix-ture to be separated; each component flows across the stationary phase at a unique rate

Separation Techniques: Distillation• Distillation is an effective method of separating

a mixture of liquids or to purify a liquid with solid particles dissolved in it

− Uses the differences in the boiling points of different components in the mixture

− Each component boils at a different temperature, therefore it is possible to boil off one liquid phase of the mixture at a time.

• Distillation is used to purify alcohol, or water, or refine oil

Separation Techniques: Crystallization

• Crystallization is a separation technique, that produces a pure solid from a solid-liquid solution− Usually involves a

supersaturated solutiono Rock candy, stalactite

and mineral formation, crystallized honey, etc.

Properties & Changes: Physical• A physical property is a characteristic that

can be observed or measured without changing the identity of the substance− temperature, density, texture, color, shape,

taste, specific heat, strength, luster, hardness, mass, odor, state, solubility, conductivity, ductility, malleability, etc.

− It generally takes several phys properties to identify a substance

Properties & Changes: Physical• There are 2 types of physical properties:

− Intensive properties, which are properties that do not depend on the amount of the matter present.o Coloro Odoro Luster o Malleable o Ductile

o Conductiveo Hardnesso Melting Pointo Boiling Point o Density

o Conductiveo Hardnesso Melting Pointo Boiling Point o Density

Properties & Changes: Physical− Extensive properties, which are properties

that do depend on the amount of matter present.o Masso Volumeo Areao Energyo Electrical Chargeo Momentum

Properties & Changes: Physical Changes

• A change in a substance that does not include a change in the identity of a substance is a physical change− Grinding, melting, cutting, boiling, etc.

• Melting and boiling are part of an important class of phys changes called changes of state− Change from one state of matter to

another (solid to liquid)

Properties & Changes: Chemical Changes

• A property that relates to a substance’s ability to undergo changes that transform it into different substances is known as a chemical property− Easier to see when substances react to form

new substances. e.g. the ability of charcoal to burn, ability of iron to rust, ability of silver to tarnish

• A change in which 1 or more substances are converted into different substances is called a chemical change or chemical reaction (rxn)

Properties & Changes: Chemical ChangesProperties & Changes: Chemical Changes• The substances that react in any chemical

rxn are called reactants− They are the ingredients

• The results of the reaction are called products

• An example of a chemical rxn would be charcoal burning− Carbon and oxygen would

be the reactants− Carbon dioxide and water

are the products

Physical vs. Chemical PropertiesPhysical vs. Chemical Properties

PHYSICALPROPERTIES

A characteristic of a substance that can be observed or measured without

changing composition.Ex: density, color, shape, hardness,

melting & boiling points2 kinds of phys properties;

Intensive and extensive

CHEMICAL PROPERTIES

The ability of a substance to undergo chem rxns and to form new substances

Ability to burn, to react, to decompose, etc.

Your Turn…Your Turn…• Classify each of the following as physical or

chemical changesPPCC

CC

CC

Moth balls gradually vaporize in a closetHydrofluoric acid attacks glass, and is used to etch calibration marks on glass utensils

A French chef making a sauce with brandy is able to burn off the alcohol from the brandy, leaving just the brandy flavoring

Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills

Properties & Changes: EnergyProperties & Changes: Energy• When physical or chemical changes occur,

energy is always involved− Energy is the capacity to do work

• Energy can be released or absorbed− It is transformed from one type to another,

o Chemical energy stored in charcoal is converted into heat energy when ignited

• Both energy and matter are conserved− They can neither be created nor destroyed− These are called the Laws of Conservation of

Matter & Energy

Properties & Changes: EnergyProperties & Changes: Energy

• We will deal more with energy later, but there are 8 different types− Kinetic Energy− Potential Energy− *Light Energy− Sound Energy− Electrical Energy− *Chemical Energy− *Heat Energy− Mechanical Energy

Pure Substances: AtomsPure Substances: Atoms• The only obvious difference between one

type of atom and another are how many electrons, protons, and neutrons the different types of atoms have

Pure Substances: ElementsPure Substances: Elements• Clusters of the same type of atoms are Clusters of the same type of atoms are

called elementscalled elements− elements are elements are pure substances pure substances that canthat can’’t be t be

decomposeddecomposed− Each element has Each element has featuresfeatures that make it that make it

unique and cause it to behave in a unique and cause it to behave in a predictablepredictable manner manner

− They are collectively organized in a huge They are collectively organized in a huge chart called the chart called the periodic table (PT)periodic table (PT)

Pure Substances: ElementsPure Substances: Elements• Each square on most Periodic Tables gives Each square on most Periodic Tables gives

information about the element that the information about the element that the square represents.square represents.

Sec 1-3Sec 1-3 Pg 20-24Pg 20-24

− Atomic NumberAtomic Number− Atomic SymbolAtomic Symbol− Atomic NameAtomic Name− Atomic WeightAtomic Weight

Pure Substances: ElementsPure Substances: Elements− Atomic NumberAtomic Numbero This number is the order that the atom is This number is the order that the atom is

on the Periodic Tableon the Periodic Tableo It also represents the number of protons It also represents the number of protons

that the atom has in its nucleusthat the atom has in its nucleus− Atomic SymbolAtomic Symbolo This is the symbolic representation of the This is the symbolic representation of the

elementelemento This symbol is used when writing chemical This symbol is used when writing chemical

formulasformulas

Pure Substances: ElementsPure Substances: Elements− Atomic NameAtomic Nameo This is the name of the element, which may This is the name of the element, which may

be named from mythology, latin, scientist of be named from mythology, latin, scientist of discovery, country of discovery, etc.discovery, country of discovery, etc.

− Atomic WeightAtomic Weighto This is a measure of the mass This is a measure of the mass

of the average atom of that element of the average atom of that elemento ItIt’’s equal to the mass of the nucleus of the s equal to the mass of the nucleus of the

average atom of that elementaverage atom of that element

Your Turn…Your Turn…• Use the clue provided to identify the Use the clue provided to identify the

elementelementBoronBoronGalliumGalliumCarbonCarbonLeadLeadAstatineAstatinePoloniumPolonium

Atomic number: 5Atomic number: 5Symbol: GaSymbol: GaAtomic weight: 12.011 Atomic weight: 12.011 Symbol: PbSymbol: PbAtomic weight: 210Atomic weight: 210Atomic number: 84Atomic number: 84

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• The PT is organized into vertical columns The PT is organized into vertical columns called called groupsgroups or or familiesfamilies..− There are There are 18 columns18 columns

• Each group contains elements with similar Each group contains elements with similar chemical characteristicschemical characteristics− for instance elements in group 2 are for instance elements in group 2 are

reactive metals with similar abilities to bond reactive metals with similar abilities to bond to other kinds of atomsto other kinds of atoms

− Or group 18 which are all gases that are Or group 18 which are all gases that are extremely resistant to chemical changeextremely resistant to chemical change

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• The horizontal rows of elements in the PT The horizontal rows of elements in the PT are called are called periodsperiods..− Physical and chem characteristics Physical and chem characteristics change change

predictably predictably across the periodacross the period− Elements close to each other tend to have Elements close to each other tend to have

similar characteristicssimilar characteristics, while elements , while elements farther apart become increasingly differentfarther apart become increasingly differento For example the elements on the far left of the For example the elements on the far left of the

PT tend to be soft, shiny solids that are good PT tend to be soft, shiny solids that are good conductorsconductors

o The far right are gasesThe far right are gases

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• The two sets of elements below the PT The two sets of elements below the PT make up what are called the make up what are called the lanthanide and lanthanide and actinide seriesactinide series..− They are metallic and radioactive and They are metallic and radioactive and

should be placed after elements 57 & 89should be placed after elements 57 & 89

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• There is another major division of the There is another major division of the elements, metals, nonmetals & metalloids.elements, metals, nonmetals & metalloids.

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• A metal is a shiny element that is a good A metal is a shiny element that is a good conductor of conductor of heat and electricityheat and electricity− At room temp, most metals are solids.At room temp, most metals are solids.o Mercury is an exception, itMercury is an exception, it’’s standard state is s standard state is

liquid (standard state is the state of matter at liquid (standard state is the state of matter at 25 25 C and 1 atm)C and 1 atm)

− Most metals are also Most metals are also malleablemalleableo That is they can That is they can

be hammered or be hammered or rolled into thin sheetsrolled into thin sheets

Pure Substances: Organization of the PTPure Substances: Organization of the PT

− Metals tend to be Metals tend to be ductileductile..o Which means they can be drawn into a fine Which means they can be drawn into a fine

wirewire− Metals behave this way because of their Metals behave this way because of their

high tensile strengthhigh tensile strengtho Tensile strength deals with its resistance Tensile strength deals with its resistance

to breaking.to breaking.o The metal atoms just realign themselves as The metal atoms just realign themselves as

the metal is being stretched or hammered. the metal is being stretched or hammered.

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• Nonmetals are elements that are poor Nonmetals are elements that are poor conductors of conductors of heat and electricityheat and electricity− Many nonmetals are gases at room Many nonmetals are gases at room

temperature (H, O, N, F, Cl)temperature (H, O, N, F, Cl)− One nonmetal is a liquid (Br)One nonmetal is a liquid (Br)− The rest tend to be The rest tend to be brittle solids brittle solids

(C, S, P, Se, I).(C, S, P, Se, I).

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• MetalloidsMetalloids are elements that have some of are elements that have some of the characteristics of metals and some of the characteristics of metals and some of nonmetalsnonmetals− on the stair step line that separates the on the stair step line that separates the

metals from the nonmetalsmetals from the nonmetals− All metalloids are All metalloids are solids at room tempsolids at room temp− Tend to be less malleable Tend to be less malleable

than metals, but not as brittle than metals, but not as brittle as nonmetals as nonmetals

− Metalloids tend Metalloids tend to be to be semiconductivesemiconductive

Pure Substances: Organization of the PTPure Substances: Organization of the PT

• The elements in the far right column are the The elements in the far right column are the noble gasesnoble gases− They are unique in that they are generally They are unique in that they are generally

unreactiveunreactive− All are gases at room tempAll are gases at room temp− Ne, Ar, Kr, and Xe are all used Ne, Ar, Kr, and Xe are all used

in lighting in lighting− Helium is used in party Helium is used in party

balloons and weather balloons and weather balloonsballoons