oral presentation pp

8/7/2019 oral presentation PP

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State of Matter


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GGroup members:roup members:

--


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IntroductionIntroduction

y Whatis matter?

anythingthat has mass and occupies volume

Consist of 3 state

x Solid

x Liquid

x Gas

y

Depends onintermolecular forces Effect oftemperature: inc temp


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Matter consist of moving particlesMatter consist of moving particles


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Class of matterClass of matter

Matter

Mixture ofsubstance

Heterogeneousmixture

Homogenousmixture

Pure substance

Compounds

elements


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Changes in matterChanges in matter

y Physical vs chemical

y Microscopic vs macroscopic


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Physical changesPhysical changes

y Changes in state butnot chemical

composition

Ex: ice and liquid, cutting wood

y The form had change butit still having

same properties (melting point, boilingpoint, chemical composition)


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y

A change in which the composition of a substance isalteredy As a result, the original properties get changed and one

or more new substances are formed.y Itis permanent change and cannot be reversed by mere

reversal of conditionsy The factors for chemical reactiontake place :

Temperature, presence of light & catalyst, electricity &pressure.

y Example: indicate that a chemical change took place : F

ormation ofgases, bubbles. Formation of precipitate (insoluble particles).

WHAT ARE CHEMICAL CHANGES?WHAT ARE CHEMICAL CHANGES?

NABILAH


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CHARACTERISTIC OFCHARACTERISTIC OF

CHEMICAL CHANGESCHEMICAL CHANGES

Neutralization - react with acids and bases

Combustion react with O2

Oxidation Redox

Precipitation

Photosynthesis Decomposition

Corrosion


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PROPERTIES OF MATTERPROPERTIES OF MATTER

EXTENSIVE

y a property whichdepends onthe size ofthe sample

y (mass, volume, length,etc.)

y eg. An ice cube is muchsmaller than iceberg

INTENSIVE

y a property which isindependent ofthe sizeofthe sample

y (color, melting/boilingpoint, density etc.)

y eg. A small ice cubemight have sametemperature as amassive iceberg.


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SUBSTANCESSUBSTANCES

y Matter of definite composition and

properties.

y Each substance has its own characteristics

and properties.y Pure substances - unique materials with

their own chemical and physical properties,

and are composed of fixed ratios of atoms


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CHARACTERISTICS OF PURECHARACTERISTICS OF PURE

SUBSTANCESSUBSTANCES

y composed ofthe same kind of particles

(eg : hydrogen, oxygen)

y homogeneous, irrespective ofits origin ormethod of preparation.

y has definite properties, characteristic ofitself.

y

has the same compositionthroughout.y can only be changes by chemical methods , not by

physical methods


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SubstanceSubstance

y Is defined as elements [ H, C, Br],

compound [ H2o, CO2] or a mixture[ water + sugar]


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substance

mixture

homogenous

heterogenous

Puresubstance

Compound

elements


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y Fixed composition

y Cannot be separated into simpler

substances by physical methods (physicalchanges)

y Can only be changed inidentity and

properties by chemical methods

y Properties do not vary

Characteristic of pure substance


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CompoundCompound

y a substance that results from a combinationoftwo or more different chemical elements

y Existin fixed ratio

y Can be decomposed into smaller substanceby chemical changes thermal decomposition [thermolysis]

Calcium carbonate decomposes into calcium

oxide and carbon dioxide when heated:CaCO3 CaO + CO2 Electric decomposition

pass electric currentthrough the compound


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ElementsElements

y An elementis a substance thatis made

entirely from one type of atom

ex: hidrogen

1 proton and 1 electron, changingthe numberof proton will change the type of elements

y Cannot be decomposed into simpler

substances by chemical changes


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MixtureMixture

y Mixture refers to the physical

combination oftwo or more substances

y there are no chemical changes to itsconstituents

y There will be changes in melting point and

boiling pointin a mixture

Difference in pure water and water with salt


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y Put another way, if a solute is dissolved ina solvent, thenthe number of solventmolecules atthe surface ofthe solutionis

less than for pure solvent.y The surface molecules canthus be

considered diluted bythe less volatileparticles of solute.The rate of exchange

between solventinthe solution and intheair above the solutionis lower (vapourpressure ofthe solventis reduced).


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y A lower vapour pressure means that a

higher temperature is necessaryto boilthe water inthe solution, hence boiling-

point elevation.y Conversely,adding common saltto water

will lower its freezing point.


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HOMOGENOUSMIXTUREHOMOGENOUSMIXTURE

y Homogenous Mixture have only one

phase,or have uniform appearancethroughout.

y It can be separated by physical means

y There is uniformityin properties and

compositionthroughout sample.

y Examples are corn oil and sugar solution.

Nabilah


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HETEROGENOUSMIXTUREHETEROGENOUSMIXTURE

y Heteregenous Mixture are made up of

more than one phase or different parts.

y It can be separated easily by means

y The different components are visiblydistinguishable from one another.

y Examples are tossed salad and a piece of

quartz contain a vein ofgold.


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SOLIDSOLID

y Major states of matter

y It has definite volume and definite shape

y It has no compressibility and has high

density.

y Molecules are held close to each other bytheir attraction of charge.They will be

vibrate, but will stayin close proximity.


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LIQUIDLIQUID

y It has definite volume and has no definite

shape.

y It has density and slight compressibility

y Molecules will flow or glide oneanother,bt motionis bit more random

thanthat of a solid.

y The particles are still close together butin anirregular arrangement


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y Liquid can flow to take their shape ofthe

container, butthey cannot easilycompressed because the molecules are

already close together.


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GASGAS

y It has no definite shape and volume

y It has low density and high compressibility

y The rapidly moving particles constantly

collide with each other and with the wallsofthe container.


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GASEOUSSTATEGASEOUSSTATE

y As mostgases are difficultto observe

directly with our senses, they aredescribed through the use of four physical

properties or macroscopic characteristics:the gass pressure, volume, number of

particles (chemists group them by moles),

and temperature.


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y PRESSUREis force exerted bygas

molecules on unit area of containerwalls.Its unitis in atm or mm Hg or

pascalsy VOLUMEis taken as the volume ofthe

container. Its unitis in liters or cubic

centimeters.y TEMPERATUREis generally measured in

kelvins or absolute degree.


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BOYLES GAS LAWBOYLES GAS LAW

y Boyle's Law simply describes the relationship betweenthepressure and volume of an enclosed gas whenTemperatureremains constant.

y

The pressure is inversely proportional to the volumeEquation for the Boyles Law :

P1V1=P2V2

where

P1: the pressure ofgas before the changeV 1: the volume ofgas before the change

P2 : the new pressure after the change

V2 : the new volume after the change

amaleena


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WhenWhenpressurepressure increaseincrease,,VolumeVolume decreasedecrease at fixed temperatureat fixed temperature


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CHARLESS GAS LAWCHARLESS GAS LAW

Charless Law can be describes the relationship betweenvolume and temperature at a constant pressure

The volume is directly proportional with thetemperature

The Charless Law equation is:

V1/T1 = V2/T2

V1: the initial volume ofthe gas

T1: the initial absolute temperature in Kelvin ( rC +273)

V2: the final ofthe volume ofthe gas

T2: the final absolute temperature in Kelvin


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The graph for Charless Law is aThe graph for Charless Law is a straight linestraight line

WhenWhentemperaturetemperature increaseincrease,, volumevolume alsoalso increaseincrease


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GAYGAY--LUSSACS LAWLUSSACS LAW

States that the pressure of the gas of fixed mass and

fixed volume is directly proportional to the gas absolutetemperature.

The Gay-Lussacs Law equation is:

P1/T1 = P2/T2

P1 : the initial pressure ofthe gas

T1

: the initial ofthe temperature ofgasP2: the final pressure ofthe gas

T2: the final temperature ofthe gas


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The graph of GayThe graph of Gay--Lussacs Law is aLussacs Law is a straight linestraight lineWhenWhenpressurepressure increaseincrease, the, the absolute temperatureabsolute temperature alsoalso increaseincrease


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COMBINED GAS LAWCOMBINED GAS LAW

y WhenBoyles Law, Charless Law and Gay Lussacs Law

combined, it will give a single equation:

P1V1 / T1 = P2V2 / T2


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AVOGADROS LAWAVOGADROS LAW

y Avogadros Law states that for a gas atconstant

pressure and temperature the volume is directlyproportional to the number of moles ofgas.

y Accordingto Avogadros Law,

V / n = k

V : volume ofthe gas

n : number of moles ofthe gas

K : constant

Standard temperature : 0rC or 273 K

Standard pressure : 1 atm


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y 6): Ideal gas law until Ideal vs Real gas

(deko al yahya


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y 7)i : Liquefication ofgas until Claudes

method(ali @nazri


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ProblemsProblems

1) Whatis the weight ofnitrogengas (propellant)in an 8 fluid ounces (fl oz) aerosol containerfilled with 6 fl oz of viscous ointment? The

container is pressurized to 104.7 psi and thetemperature is 25C.

(1 fl oz = 29.57 mL; 1 atm = 14.696 psi)

Answer: 0.476g


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2)If 3 fl oz ofthe aerosol in (1)is dispensed, whatis the resulting pressure (in psi)inthe container?

Answer: 41.7 psi

3)14.4 grams of an unknowngas is found to have avolume of 8.00 L at 760 torr and 25oC. Whatisthe molecular mass ofthe gas? (1 atm = 760torr)

Answer: 44.0 g/mol

Problems (cont.)Problems (cont.)


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Changes ofMatterChanges ofMatter


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Changes ofMatterChanges ofMatter


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SOLID

CRYSTALLI

NE SOLID-highly regulararrangement of

atoms, ions,molecules- periodic

(repeating)

AMORPHOUS

SOLID-no repeating

pattern,-only short range

order,

-extensivelydisordered- non crystalline

(e.g. glasses)


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SOLID CRYSTALLINESOLID CRYSTALLINE

y It has fixed geometric patterns or lattices.y It has a definite shape and orderly arrange unity It has sharp melting point

y Itis divided into seven distinct forms.y high degree of order solid formy 2 types of solid which are crystalline and

amorphous solid a.k.a non-crystalline solid.

y Non crystalline solids have much more orderthan liquid and gases.y The molecules of solid are held together by

strong bonds which impart a high melting point.


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77 CRYSTAL SYSTEMCRYSTAL SYSTEM


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y The simplest repeating unitin a crystal iscalled a unit cell.

y Each unit cell is defined interms oflattice

points the points in space about which the particles are

free to vibrate in a crystal.


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SIMPLE CUBIC CELLSIMPLE CUBIC CELL

y Simple cubic unit cell is thesimplest repeating unit ofthesimple cubic structure

y Each corner ofthe unit cell isdefined by a lattice point at

which an atom, ion, ormolecule can be found inthecrystal.

y The edge of a unit cell alwaysconnects equivalent points.

y Each ofthe eight corners ofthe unit cell therefore mustcontain anidentical particle.

y A simple cubic has eightequivalent particles ontheeight corners.


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BODYBODY--CENTERED CUBICCENTERED CUBIC

y The body-centeredcubic unit cell is thesimplest repeating unitin a body-centeredcubic structure.

y There are eightidentical particles onthe eight corners ofthe unit cell.

y

Atthis time there is aninth identical particleinthe center ofthebody ofthe unit cell.


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FACEFACE--CENTERED CUBICCENTERED CUBICy

It has identical particles onthe eight corners ofthecube.

y It has same particles inthecenters ofthe six faces ofthe unit cell, for a total of14 identical lattice points.

y The face-centered cubicunit cell is the simplestrepeating unitin a cubicclosest-packed structure.

y The presence of face-centered cubic unit cells inthis structure explains whythe structure is knownas cubicclosest-packed


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PREPARATION OF CRYSTALSPREPARATION OF CRYSTALS

y Itis actually a change from the liquid to the solid state

y METHOD #1 This state can done by cooling a molten sample to below its melting.

Examples : suppositories, creams and semisolid matrix dosage forms.

y METHOD #2 We need a solution of a material and change the system to solid form

through supersaturated solution.

INFO:

y The process to form crystal called as nucleation and growth.

Nucleationis the formation of a small mass onto which a crystal cangrow.

Growth is the addition of more solute molecules to the nucleation site


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POLYMORPHISMSOLIDSPOLYMORPHISMSOLIDS

y When a substance exists in more than onecrystalline form, the different forms aredesignated as polymorphs and the phenomenonas polymorphism .

y The polymorphs differ from each other accordingto their physical properties such as solubility,

melting point

Density hardness and

compression properties.


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22TYPES OF POLYMORPHSTYPES OF POLYMORPHS

1. Enantiotropic polymorph It can be reversibly changed into another

form by alteringthe temperature andpressure

e.g. sulfur.

2. Monotropic polymorph

Itis unstable at all temperatures andpressure

e.g. glyceryl stearates.


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SUBLIMATIONSUBLIMATION

y Definition:The process occurs when a

material changes from a frozen solid toa gas without passing through the

intermediate liquid state.

y E.g.- camphor, menthol, dryice (frozen

CO2)


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WaterWater

y AB = melting point at different pressure,Alongthe curveAB, the solid exists in equilibrium with its liquid phase.


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Frozen COFrozen CO22 (DryIce)(DryIce)


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Frozen COFrozen CO22 (DryIce)(DryIce)


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Vapor pressureVapor pressure


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y Figure 1 shows liquid water intwo containers

(one open and another closed connected to amanometer tube).y Inthe open container, the molecules ofthe liquid

water escape as vapor, while molecules intheclosed container escape as vapor with a rise in

pressure.y The vapor molecules exert a pressure known as

the vapor pressure.


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y As the concentration ofthe vapor moleculesincreases, thus they are in a more random statecausingthe molecules to strike the surface oftheliquid water and become trapped bytheintermolecular forces ofthe liquid water.

y Condensation occurs.y Whenthe rate of vaporizationis balanced bythe

rate of condensation, the system is said to be in astate ofdynamic equilibrium.

y The equilibriumvapor pressure is thepressure measured when dynamic equilibrium is

achieved.y The higher the temperature, the higher the vapor

pressure.


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Boiling pointBoiling point

y The boiling point is the temperature at which the vaporpressure of a liquid is equal to the external pressure.

y Atthe boiling point, bubbles form withinthe liquid.

y The pressure exerted onthe bubble is largely atmosphericpressure and some hydrostatic pressure.

y The pressure inside the bubble is due to the vapor pressure.y The bubbles rise to the surface ofthe liquid, breaking apart

from the intermolecular forces, and burst as vapor.

y Ifthe vapor pressure is lower thanthe external pressure, thebubbles would collapse before it could rise.

y The boiling point of any liquid is determined byitsintermolecular forces.


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Melting pointMelting point

y The melting point of a solid is thetemperature at which solid and liquidphases coexistin equilibrium (Liquid-Solid

equilibrium).


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Relative HumidityRelative Humidity

y Definition: the amount of water vapor inthe air at anygiventime thatis usuallyless thanthat required to saturate the air.

y It can be generally calculated bythisformula:

y

y The most common unit for relativehumidity is g/m3.


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y Relative humidity does notimplythatthe airholds the water vapor but rather as a means oftransporter of water vapor.

y In fact, a volume without air can contain watervapor and relative humidity can bedetermined.

y When water vapor reaches saturation at a giventemperature, in other words, the system hasreached the dew point, and the vapor molecules

condense into liquid water or dew.y Example: the tiny water droplets in a bottle of

water.


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ibbs Phase RuleGibbs Phase Ruley Itis expressed bythe simple formulation:

y F=CP+2

y Where;

y C is the number of components inthe system;

y P is the number of phases inthe system;

y Fis the degree of freedom (variance)i.e. the number ofvariable conditions such as temperature, pressure andcompositionto define the state ofthe system at equilibrium.

y

y The Gibbs phase rule can be used for pure substance samplesand ideal solutions oftwo or more substances.

y It can be further appreciated by means of a phase diagram.


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Graph:Phase diagram of waterGraph:Phase diagram of water


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y

y Inthe one-phase regions (ice, liquid water or

vapor water), the number of component, C=1,the number of phase, P=1, hence the degree offreedom, F=2.

y We can either varythe degree oftemperature,or pressure or both without crossingthe phaseline under certain limits thatis the critical point.

y Alongthe phase line, we have two phases inequilibrium with each other (solid-liquid, solid-gasor liquid-gas phase), the number of component,

C=1, the number of phase, P=2, hence the degreeof freedom, F=1.


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y If we wantto stay onthe phase line, we cannotchange the pressure or temperature arbitrarily

otherwise we go offthe line and we no longerhave 2 phases in equilibrium.y In other words, if we increase the temperature,

we must also increase the pressure in order tohave 2 phases existin equilibrium.

y There is only one point onthe diagram where allthree phases can existin equilibrium and itisknown as the triple point.

y Since the number of phase is 3, the degree of

freedom is 0, thus we need to maintainthepressure and temperature in order to be onthatpoint.

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