Pcm chapter-01-part a

PCM 0035PCM 0035GENERALCHEMISTRYGENERALCHEMISTRY

Chapter 1 Chapter 1 Part APart A

Chemistry: Chemistry: Basic Concepts,Basic Concepts,

Reactions & StoichiometryReactions & Stoichiometry

1.1 1.1 MixturesMixtures,, Elements Elements & & CompoundsCompounds

1.2 An 1.2 An Atomic Overview Atomic Overview of of MatterMatter

1.3 1.3 DaltonDalton’s ’s Atomic TheoryAtomic Theory

1.4 The 1.4 The Atomic Theory TodayAtomic Theory Today

1.5 1.5 CompoundsCompounds, , FormulasFormulas, , NamesNames && MassesMasses

1.6 1.6 MixturesMixtures: : ClassificationClassification & & SeparationSeparation

1.7 The 1.7 The MoleMole

1.8 Determining 1.8 Determining thethe FormulaFormula of an of an UnknownUnknown CompoundCompound

1.9 1.9 WritingWriting & & Balancing Chemical EquationsBalancing Chemical Equations

1.10 Calculating 1.10 Calculating AmountsAmounts ofof ReactantReactant & & Product Product

Chemistry: A Chemistry: A CentralCentral Science Science

ChemistryChemistry is the is the study of matter study of matter & &

the the changeschanges that it undergoes that it undergoes

A A basic knowledge basic knowledge of of chemistrychemistry is essential for students of is essential for students of

BiologyBiology, , PhysicsPhysics, , EcologyEcology, etc., etc.

BiochemistryBiochemistry►►Molecular Biology Molecular Biology

►►Immunology Immunology ►►EndocrinologyEndocrinology

BiochemistryBiochemistry►►Molecular Biology Molecular Biology

►►Immunology Immunology ►►EndocrinologyEndocrinology

MedicineMedicine►►Pharmacology Pharmacology

►►Clinical Chemistry Clinical Chemistry ►►NutritionNutrition

MedicineMedicine►►Pharmacology Pharmacology

►►Clinical Chemistry Clinical Chemistry ►►NutritionNutrition

PlantPlant ScienceScience

►►Botany Botany ►►AgronomyAgronomy

PlantPlant ScienceScience

►►Botany Botany ►►AgronomyAgronomy

PhysicsPhysics►►Atomic Atomic & Nuclear & Nuclear

SpectroscopySpectroscopy►►MaterialsMaterials

PhysicsPhysics►►Atomic Atomic & Nuclear & Nuclear

SpectroscopySpectroscopy►►MaterialsMaterials

BiologyBiology►►Microbiology Microbiology ►►Physiology Physiology

►►GeneticsGenetics

BiologyBiology►►Microbiology Microbiology ►►Physiology Physiology

►►GeneticsGenetics

CHEMISTRYCHEMISTRY

GeologyGeologyGeologyGeology

Environmental Environmental ScienceScience►►Ecology Ecology ►►PollutionPollution

Environmental Environmental ScienceScience►►Ecology Ecology ►►PollutionPollution

As AAs A CENTRAL CENTRAL ScienceScience

AstronomyAstronomyAstronomyAstronomy

Chemistry in our daily lifeChemistry in our daily life::

- baking soda to leaven bread- baking soda to leaven bread- pressure cooker to - pressure cooker to shorten cooking timeshorten cooking time- squeeze lemon juice - squeeze lemon juice overover sliced pears sliced pears toto prevent prevent them from turning them from turning brownbrown

MixturesMixtures, , ElementsElements & & CompoundsCompounds

•MatterMatter is anything that is anything that occupiesoccupies spacespace & has & has massmass. .

•E.g. water, earth, air & treesE.g. water, earth, air & trees

•Classifications: Classifications:

SubstancesSubstances,, MixturesMixtures, , ElementsElements, , CompoundsCompounds..

1.1.

3.3.2.2.

4.4.


1.1. SubstanceSubstance :: matter that has a definite matter that has a definite compositioncomposition & & distinctdistinct propertiesproperties..

Differ from one another in composition Differ from one another in composition & & can be identified by can be identified by appearanceappearance, , smellsmell, ,

tastetaste & & other propertiesother properties..

e.g. e.g. water, ammonia, water, ammonia, sucrose, gold, oxygensucrose, gold, oxygen

2.2. MixtureMixture ::

Can be either Can be either ::a) a) HomogeneousHomogeneous mixturemixture

e.g. soft drink, milke.g. soft drink, milkb) b) HeterogeneousHeterogeneous mixturemixture

e.g. cement, iron filings in sande.g. cement, iron filings in sand

combination of combination of 2 or more substances 2 or more substances -substances retain -substances retain distinct identitiesdistinct identities

– – composition composition samesame throughout.throughout.

– – composition composition notnot uniformuniform throughout.throughout.


2.2. MixtureMixture ::Any mixture can be created & then Any mixture can be created & then

separated by separated by physicalphysical means means

Use a Use a magnetmagnet to separate to separate

a a mixture of mixture of sandsand & & ironiron

into into purepure components components without changing without changing the identities of components.the identities of components.


3. 3. ElementElement :: substance substance thatthat cannotcannot bebe separated separated intointo simpler substances simpler substances byby chemicalchemical means means..

• 118118 ((Feb 2010Feb 2010) ) elementselements have been identified:have been identified:

• 94 elements 94 elements foundfound naturallynaturally onon Earth Earth e.g. e.g. goldgold ( (AuAu), ), aluminum aluminum ((AlAl), ), leadlead ( (PbPb), ), oxygenoxygen ( (OO), ), carboncarbon ( (CC).).

• Certain elements Certain elements createdcreated by scientists. by scientists. e.g. technetium, mericium, seaborgium.e.g. technetium, mericium, seaborgium.


3. Element3. Element ::MixturesMixtures, , ElementsElements & & CompoundsCompounds

3. Element3. Element ::

Fire Fire retardantretardant

PaintsPaints

CosmeticsCosmetics

PesticidesPesticides

ShineShine

ToothpasteToothpaste

MedicineMedicine

ConstructionConstruction

PigmentPigment

FireworksFireworksFertilizerFertilizer

FertilizerFertilizer

AlloyAlloy

AlloyAlloy

Semi Semi ConductorConductor


4. Compound 4. Compound ::

- - OnlyOnly bebe separated separated intointo pure components pure components ((elementselements) ) by by chemicalchemical meansmeans..

WaterWater (H(H22O)O)

AmmoniaAmmonia (NH(NH33))

GlucoseGlucose (C(C66HH1212OO66))

substancesubstance composed of composed of atoms of atoms of two/more elementstwo/more elements chemicallychemically unitedunited in in fixed proportionsfixed proportions..


Summary:Summary:

HHomogeneousomogeneousMMixturesixtures

HHeterogeneouseterogeneousMMixturesixtures CCompoundsompounds EElementslements

Separation by Separation by chemicalchemical methods methods

Pure Pure SubstancesSubstancesMixturesMixtures Separation by Separation by

physical physical methodsmethods


MatterMatter

•• Based on Dalton’s Based on Dalton’s Atomic Theory Atomic Theory →→

• Later, demonstrated that atoms possess internal Later, demonstrated that atoms possess internal structure - (made up of even smaller particles)structure - (made up of even smaller particles)

The Structure of AtomsThe Structure of Atoms

AtomAtom →→ basicbasic unitunit of an of an elementelement that can that can enter into enter into chemical combinationchemical combination

protonproton

neutronneutron

nu

c leus

nu

c leus

CloudCloud of of electronselectrons

AtomAtom →→ extremely small & indivisible extremely small & indivisible

In a In a neutralneutral atom, atom,number of protons = number of protons = number of number of electronselectrons

► Way to Way to denotedenote an element (an element (XX):): XXA

A

ZZ

►► Atomic number Atomic number ((ZZ)) = no. = no. of of protonsprotonsin in nucleusnucleus

►► Mass number Mass number ((AA)) = = no. no. ofof neutronsneutrons

∴∴Atomic number Atomic number ((ZZ)) →→ number of number of electronselectrons

&& protonsprotons

Atomic NumberAtomic Number, , Mass NumberMass Number, & , & IsotopesIsotopes

Isotopes:Isotopes: atomsatoms withwith samesame atomic number atomic number ((ZZ) )

but but differentdifferent mass number mass number ((AA))

E.g. there are E.g. there are 33 isotopesisotopes of hydrogen:of hydrogen:

HH HH HH11

111122 33

11

hydrogenhydrogen deuteriumdeuterium tritiumtritium

Atomic NumberAtomic Number, , Mass NumberMass Number, & , & IsotopesIsotopes

MoleculesMolecules

AllotropesAllotropes

AtomsAtoms** **

IonsIons

An An aggregateaggregate of of at leastat least 2 atoms in a 2 atoms in a definite arrangement held together by definite arrangement held together by

chemical bondschemical bonds.. didiatomicatomic molecule molecule →→ contains only 2 atoms contains only 2 atoms

polypolyatomicatomic molecule molecule →→ more than 2 atomsmore than 2 atoms

MoleculesMolecules

chemical bondschemical bonds

COCO22 CC22HH55OHOH

NN22 Molecule?Molecule?

►► AAn atom or a group of atoms that n atom or a group of atoms that has a has a netnet positivepositive or or negativenegative chargecharge..

CationCation →→ ion with a net ion with a net positivepositive chargecharge..AnionAnion →→ ion ion whosewhose net net chargecharge is is negativenegative..

CationCation + + AnionAnion →→ ionic compoundionic compound, e.g. , e.g. NaNaClCl

MonoMonoatomic ions atomic ions →→ Na Na++, Mg, Mg2+2+, Fe, Fe3+3+, etc. , etc.

PolyPolyatomic ions atomic ions →→ OHOH––, CN, CN––, NH, NH44++, etc. , etc.

IonsIons

An An allotropeallotrope is: is: one of one of two two oror more more distinct distinct formsforms of an of an elementelement

e.g. Oe.g. O22 && O O33

What are 2 What are 2 commoncommon allotropicallotropic forms of forms of carboncarbon??

OO22 OO33

AllotropeAllotrope

Exist in multiple structures but differ in propertiesExist in multiple structures but differ in propertiesAllotropesAllotropes

Diamond Diamond & & GraphiteGraphite

Types of Chemical FormulaTypes of Chemical Formula

A chemical formula is used to A chemical formula is used to express express compositioncomposition of of

molecules & ionic compounds molecules & ionic compounds in terms of chemical symbols.in terms of chemical symbols.

Molecular FormulaMolecular Formula

Empirical FormulaEmpirical Formula

Molecular FormulaMolecular Formula

shows shows exactexact number of atoms number of atoms of each element in of each element in

smallest unit of a substance.smallest unit of a substance.

OO22

e.g. He.g. H22

HH22OO

Empirical FormulaEmpirical Formula

e.g. e.g. molecular formula molecular formula for for hydrogen peroxidehydrogen peroxide is is

HH22OO22

The The empirical formula empirical formula of of hydrogen peroxide hydrogen peroxide isis

HH OO

Tells us Tells us whichwhich elementselements areare present & the present & the simplestsimplest whole number whole number ratioratio ofof theirtheir atomsatoms, ,

but but notnot necessarily the necessarily the actualactual number of number of atoms in a given molecule.atoms in a given molecule.

CC66HH1212OO66 ? ? Continued…….Continued…….

Education

Pcm chapter-01-part a