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Chemical Foundations Chemical Foundations Chapter 1 Chapter 1

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Chemical FoundationsChemical Foundations

Chapter 1Chapter 1

Scientific MethodScientific Method

– – process of process of studying natural studying natural phenomena, phenomena, involving involving observations, observations, forming laws, and forming laws, and theories, and theories, and testing of theories testing of theories by by experimentationexperimentation

Step to the Scientific Step to the Scientific MethodMethod

1.1. Observation Observation – use senses– use senses

Qualitative Qualitative -- descriptive, -- descriptive, nonnumericnonnumeric

QuantitativeQuantitative -- results in a definite -- results in a definite form, usually as numbers and form, usually as numbers and units.units.

2. Formulating a Hypotheses – possible explanation for what is observed

3. Performing Experiment – running tests to see if hypothesis is true

• Theory (Model)Theory (Model) – a set of tested – a set of tested hypotheses that gives a overall hypotheses that gives a overall explanation of some natural explanation of some natural phenomenon.phenomenon.

• A theory is an interpretation of why A theory is an interpretation of why nature behaves in a particular way.nature behaves in a particular way.

International System of International System of measurements (SI system) measurements (SI system)

• Based on the metric system and Based on the metric system and units derived from the metric units derived from the metric systemsystem

The Fundamental SI UnitsThe Fundamental SI Units

Physical Quantity Name of Unit Abbreviation

Mass Kilogram Kg

Length Meter m

Time Second s

Temperature Kelvin K

Amount of Substance

mole mol

Metric PrefixesMetric Prefixes

• G = Giga = 10G = Giga = 1099

• M = Mega = 10M = Mega = 1066

• k = kilo = 10k = kilo = 1033

• h = hecto = 10h = hecto = 1022

• da = deka = 10da = deka = 1011

• Base = 10Base = 1000

• d = deci =10d = deci =10-1-1

• c = centi =10c = centi =10-2-2

• m = milli =10m = milli =10-3-3

• μ = micro =10μ = micro =10-6-6

• n = nano =10n = nano =10-9-9

• p = pico = 10p = pico = 10-12-12

SIGNIFICANT FIGURESSIGNIFICANT FIGURES

To determine the To determine the number of significant number of significant figures in a written figures in a written number complete one of number complete one of the following:the following:

Uncertainty of Uncertainty of measurementmeasurement

• Accuracy = How close to the true Accuracy = How close to the true value you arevalue you are

• Precision = How close your Precision = How close your measurements are to each othermeasurements are to each other

• Random Error Random Error – means a measurement – means a measurement has the probability of being high or has the probability of being high or low; this occurs in estimating the value low; this occurs in estimating the value of the last digit of a measurement.of the last digit of a measurement.

• Systematic error Systematic error – occurs in the same – occurs in the same direction each time; either always high direction each time; either always high or always lowor always low

Rules for Counting Sig FigsRules for Counting Sig Figs

1.1. Nonzero integersNonzero integers

2.2. Leading zeros ex. 0.0025Leading zeros ex. 0.0025

3.3. Captive zeros ex. 1001Captive zeros ex. 1001

4.4. Trailing zeros ex. 1020 or 1.00Trailing zeros ex. 1020 or 1.00

5.5. Exact numbers – infinite numberExact numbers – infinite number

1. Qualifying statement: The 1. Qualifying statement: The numerical value has numerical value has no decimal no decimal placeplace written. written.

Action to takeAction to take:: Count from the first Count from the first non-zero digit to the last non-zero non-zero digit to the last non-zero digit.digit.

Examples: Examples: 18,00418,004 - 5 significant digits - 5 significant digits10,0410,040,000– 4 sig digs0,000– 4 sig digs110 – 1 sig dig0 – 1 sig dig

2. Qualifying statement: The 2. Qualifying statement: The numerical value contains a numerical value contains a decimal place.decimal place.

Action to takeAction to take:: Count from Count from the first non-zero digit to the the first non-zero digit to the end end of the number.of the number.

Examples:Examples:100.00100.00 – 5 sig digs – 5 sig digs1,0501,050. – 4 sig digs. – 4 sig digs0.000 0.000 145 00145 00 – 5 sig digs – 5 sig digs

Extra NumbersExtra Numbers

• Numbers that were NOT obtained Numbers that were NOT obtained using measuring devices but were using measuring devices but were determined by countingdetermined by counting

• Ex: 10 experiments, 3 apples, 8 Ex: 10 experiments, 3 apples, 8 moleculesmolecules

PracticePractice

A.A. 1030010300

B.B. 1.03 x 101.03 x 102323

C.C. 0.0040500.004050

D.D. 10 apples10 apples

Rules for math functionsRules for math functions

1.1. Multiplication or divisionMultiplication or division The answer should have the same The answer should have the same

number of sig figs as the least number of sig figs as the least precise measurementprecise measurement

Example: 1.34 x 0.04 = .05Example: 1.34 x 0.04 = .05

Rules for math functionsRules for math functions

2.2. Addition or SubtractionAddition or Subtraction The answer should have the same The answer should have the same

number of number of decimaldecimal places as the places as the least precise measurementleast precise measurement

Example: 1.34 + 2.3 = 3.6Example: 1.34 + 2.3 = 3.6

Dimensional AnalysisDimensional Analysis

• Converting from one system of units Converting from one system of units to anotherto another

Sample: Convert inches to Sample: Convert inches to centimeters (1 in = 2.54 cm)centimeters (1 in = 2.54 cm)

7.O0 inches = ________________cm 7.O0 inches = ________________cm

Multistep Dimensional Multistep Dimensional AnalysisAnalysis

Kilometers – meters – yards – milesKilometers – meters – yards – miles

Must have conversion factors for each Must have conversion factors for each step. step.

TemperatureTemperature

• K = K = ooC + 273.15C + 273.15

oror• ooC = K – 273.15C = K – 273.15

• ooC = (C = (ooF – 32) 5/9F – 32) 5/9

oror• ooF = (F = (ooC x 9/5) + 32C x 9/5) + 32

5.65

9

PracticePractice

A.A. Convert 15Convert 15ooF to F to coco

B.B. Convert 310K to Convert 310K to ofof

DensityDensity – the relationship between an – the relationship between an objects mass and its volume.objects mass and its volume.

The denser object will be on the bottomThe denser object will be on the bottom

Density = Mass / Volume (D = M / V)Density = Mass / Volume (D = M / V)

Example: D = ? If the mass of an object Example: D = ? If the mass of an object is 114 g and takes up a volume of is 114 g and takes up a volume of 10.0 ml. 10.0 ml.

D = 11.4 g/ml.D = 11.4 g/ml.

Matter FlowchartMatter FlowchartMATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture

Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition

uniform? noyes

Colloids Suspensions

Pure SubstancesPure Substances

• ElementElement– composed of identical atomscomposed of identical atoms– EXEX: copper wire, aluminum foil: copper wire, aluminum foil

Pure SubstancesPure Substances

• CompoundCompound

– composed of 2 or more composed of 2 or more elements in a fixed ratioelements in a fixed ratio

– properties differ from properties differ from those of individual those of individual elementselements

– EXEX: table salt (Nail): table salt (Nail)

Pure SubstancesPure Substances

For example…For example…

Two different compounds, each has a definite composition.

MixturesMixtures

• Variable combination of 2 or more pure Variable combination of 2 or more pure substances.substances.

Heterogeneous Homogeneous

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MixturesMixtures

• A physical blend of two or more A physical blend of two or more substances.substances.

Types of Mixtures:Types of Mixtures:

1.1. Homogeneous ( Solution)Homogeneous ( Solution)

2.2. HeterogeneousHeterogeneous

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Homogeneous MixtureHomogeneous Mixture

• One that has a completely One that has a completely uniform compositionuniform composition

→ → components are evenly components are evenly distributed throughout the distributed throughout the sample ex. Salt solutionsample ex. Salt solution

→→ it has a single phaseit has a single phase

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Heterogeneous MixtureHeterogeneous Mixture

• One that is not uniform in One that is not uniform in compositioncomposition

→ → has two or more phaseshas two or more phases

Ex. Oil and water, salad, milkEx. Oil and water, salad, milk

Classification of MatterClassification of Matter

• CopperCopper

• CokeCoke

• Pure waterPure water

• Sandy waterSandy water

States of MatterStates of Matter

SolidSolid – definite shape & definite – definite shape & definite volume; particles are packed volume; particles are packed closely togetherclosely together

LiquidLiquid – definite volume, but takes – definite volume, but takes the shape of the container; the shape of the container; particles close, but able to move particles close, but able to move around. Liquids flow, almost around. Liquids flow, almost incompressible and expand when incompressible and expand when heated.heated.

• GasGas – indefinite shape & – indefinite shape & volume; particles are spread far volume; particles are spread far apart. Gases expand to apart. Gases expand to completely fill the containercompletely fill the container

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States of MatterStates of Matter

Property Solid Liquid GasShape Definite Indefinite Indefinite

Volume Definite Definite Indefinite

Expansion on heating

Very slight Moderate Great

Compressibility Nil Almost nil Large

Structural

arrangement

Closely packed

Moderate -

flows

Far apart

(move freely)

Ways to separate a Ways to separate a MixtureMixture

1.1. Distillation = separating a Distillation = separating a solution with different boiling ptssolution with different boiling pts

1.1. Filtration = separate a solid and Filtration = separate a solid and liquid mixtureliquid mixture

2.2. Chromatography = used to Chromatography = used to separate mixtures by their separate mixtures by their polarity polarity

• Physical ChangePhysical Change

• Chemical ChangeChemical Change

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Changes in MatterChanges in Matter

• Freezing: liquidFreezing: liquid→ → solid solid • Melting: solid Melting: solid → → liquidliquid• Evaporation: liquid Evaporation: liquid → → gasgas• Condensation: gas → liquidCondensation: gas → liquid• Sublimation: solid → gasSublimation: solid → gas

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• Extensive propertiesExtensive properties: physical : physical properties that depend on the properties that depend on the amount of substance present ex. amount of substance present ex. mass, lengthmass, length

• Intensive propertiesIntensive properties: physical : physical properties that are not dependent on properties that are not dependent on the amount of substance present ex. the amount of substance present ex. Density, melting pointDensity, melting point

Chapter 1 Questions Chapter 1 Questions (p. 32-37)(p. 32-37)

# 23, 26, 32, 34, 46, 48, # 23, 26, 32, 34, 46, 48, 50, 56, 58, 62, 70, 72, 50, 56, 58, 62, 70, 72, 74, 80, 82, 8974, 80, 82, 89

Atoms, Molecules, and Atoms, Molecules, and IonsIons

Chapter 2Chapter 2

Law of Conservation of MassLaw of Conservation of Mass

• Mass is neither created nor Mass is neither created nor destroyed destroyed

Law of Definite ProportionLaw of Definite Proportion

• Given compound always contains Given compound always contains exactly the same proportion of exactly the same proportion of elements elements

Law of Multiple ProportionsLaw of Multiple Proportions

• When two elements form a series When two elements form a series of compounds, the ratios of the of compounds, the ratios of the masses of the second element that masses of the second element that combine with 1 gram of the first combine with 1 gram of the first element can always be reduced to element can always be reduced to small whole numbers.small whole numbers.

Models of AtomsModels of Atoms

Atomic Models:Atomic Models:• Chemical properties of atoms, ions, and Chemical properties of atoms, ions, and

molecules are related to the arrangement molecules are related to the arrangement of the electrons within them.of the electrons within them.

• John Dalton:John Dalton: 1 1stst atomic model & atomic model & considered the atom as a solid indivisible considered the atom as a solid indivisible mass. Arranged by atomic masses or mass. Arranged by atomic masses or atomic weights.atomic weights.

Dalton’s Atomic TheoryDalton’s Atomic Theory

1. All elements are composed of tiny indivisible 1. All elements are composed of tiny indivisible particles called atoms.particles called atoms.

2. Atoms of the same element are identical. The atoms 2. Atoms of the same element are identical. The atoms of any one element are different from those of any of any one element are different from those of any other element.other element.

3. 3. Atoms of different elements can physically mix Atoms of different elements can physically mix together or can chemically combine.together or can chemically combine.

4. Chemical reactions occur when atoms are 4. Chemical reactions occur when atoms are separated, joined, or rearranged. Atoms of separated, joined, or rearranged. Atoms of element are never changed into atoms of element are never changed into atoms of another element as a result of a chemical another element as a result of a chemical reaction.reaction.

• J.J. Thomson:J.J. Thomson: revised Dalton’s revised Dalton’s model by proposing that electrons model by proposing that electrons were stuck to the outside of the were stuck to the outside of the atom.atom.

• Ernest Rutherford: Ernest Rutherford: proposed the proposed the nuclear atom, in which electrons nuclear atom, in which electrons surround a dense nucleus composed surround a dense nucleus composed of protons and neutrons.of protons and neutrons.

• Chadwick:Chadwick: discovered the discovered the neutron.neutron.

• Niles Bohr: Niles Bohr: student of Rutherford; student of Rutherford; proposed that electrons are proposed that electrons are arranged in concentric circular arranged in concentric circular paths (orbits) around the nucleus.paths (orbits) around the nucleus.

AtomsAtoms – tiny particles that – tiny particles that make up mattermake up matter

Structure of Atoms:Structure of Atoms:• NucleusNucleus – center of the atom – center of the atom

• protonsprotons – positively charged subatomic – positively charged subatomic particles that is found in the nucleus; dictates particles that is found in the nucleus; dictates the identity of the atom the identity of the atom

• NeutronNeutron: subatomic particle with no : subatomic particle with no charge; found in the nucleuscharge; found in the nucleus

- Discovered by James Chadwick- Discovered by James Chadwick

• ElectronElectron: negatively charged; : negatively charged; found outside the nucleus found outside the nucleus ( electron cloud)( electron cloud)

- Discovered by J.J. Thomson using a - Discovered by J.J. Thomson using a cathode raycathode ray - the rays were - the rays were attracted to a metal plate of attracted to a metal plate of positive charge.positive charge.

Atomic NumberAtomic Number - the # of - the # of protons in the nucleus protons in the nucleus

- the # of protons = the # of - the # of protons = the # of electronselectrons

Mass NumberMass Number – total # of – total # of protons & neutrons in an atomprotons & neutrons in an atom

- To find the # of neutrons - To find the # of neutrons subtract the mass # from the subtract the mass # from the atomic #atomic #

Example:Example: Nitrogen ( Nitrogen (141477N)N)

Mass number = 14Mass number = 14

Atomic number = 7Atomic number = 7

# of protons = 7# of protons = 7

# of electrons = 7# of electrons = 7

# of neutrons = 14 – 7= 7# of neutrons = 14 – 7= 7

• Isotopes Isotopes - Has the same # of - Has the same # of protons, but different #’s of protons, but different #’s of neutronsneutrons

• Atomic Mass Unit (AMU)Atomic Mass Unit (AMU) – – 1/12 the mass of carbon1/12 the mass of carbon

• Average atomic massAverage atomic mass: : weighted weighted average of the masses of the average of the masses of the isotopes of an elementisotopes of an element

PERIODIC TABLEPERIODIC TABLE

Periodic TablePeriodic Table – an arrangement of – an arrangement of elements according to similarities in elements according to similarities in their propertiestheir properties

There are 92 naturally occurring There are 92 naturally occurring elements.elements.

Dmitri MendeleevDmitri Mendeleev – drew the first – drew the first periodic table; Russian chemist periodic table; Russian chemist arranged the first periodic table of arranged the first periodic table of elements in 1871. Arranged by atomic elements in 1871. Arranged by atomic massmass

* * The periodic table contains The periodic table contains chemical symbol, atomic number, & chemical symbol, atomic number, & average atomic mass, physical state average atomic mass, physical state of each element, group numbers, of each element, group numbers, and electron configuration.and electron configuration.

• Moseley:Moseley: Later arranged the Later arranged the periodic table by atomic number. periodic table by atomic number. (Which is the one we use today.)(Which is the one we use today.)

MODERN TABLEMODERN TABLE

• PeriodsPeriods – horizontal rows (7 total) – horizontal rows (7 total)

• GroupsGroups – vertical columns (has similar – vertical columns (has similar physical & chemical properties)physical & chemical properties)

• Metals Metals – high electrical conductivity, – high electrical conductivity, luster, ductile, & malleable (Group 1 & luster, ductile, & malleable (Group 1 & 2A)2A)

- Alkali Metals – Group 1A- Alkali Metals – Group 1A- Alkaline Earth Metals – Group 2A- Alkaline Earth Metals – Group 2A

Transition Metals & Inner Transition Metals & Inner Transition MetalsTransition Metals – make up – make up Group B (1B – 8B)Group B (1B – 8B)

NonmetalsNonmetals – poor conductors, – poor conductors, non lustrousnon lustrous- Halogens – 7A- Halogens – 7A- Noble Gases – 0- Noble Gases – 0

MetalloidsMetalloids – elements that – elements that border the stair step lineborder the stair step line

Group # = the outermost Group # = the outermost electronselectrons

Periodic TrendsPeriodic Trends

• The elements on the periodic The elements on the periodic table are arranged periodically table are arranged periodically so that trends can be so that trends can be recognized…recognized…

Trend of IonsTrend of Ions

1. You can determine the charge of 1. You can determine the charge of an ion by what group it is in.an ion by what group it is in.

1A = +11A = +1 5A = -35A = -3

2A = +22A = +2 6A = -26A = -2

3A = +33A = +3 7A = -17A = -1

4A = 4A = +/-+/- 4 4

Trend of Electronegativity Trend of Electronegativity

• This refers to the ability of an atom This refers to the ability of an atom to attract the electrons of another to attract the electrons of another atom to it.atom to it.

• Increases across the period (left Increases across the period (left – right)– right)

• Decreases down the group (top – Decreases down the group (top – bottom)bottom)

Trend of Electron affinityTrend of Electron affinity

• Measure of the tendency for atoms to Measure of the tendency for atoms to gain electrons.gain electrons.

• Increases across the period; this is Increases across the period; this is caused by the filling of the valence shellscaused by the filling of the valence shells

• Decreases down the group; this is due to Decreases down the group; this is due to the electron entering an orbital far away the electron entering an orbital far away from the nucleusfrom the nucleus

Trend of Ionization EnergyTrend of Ionization Energy

• The exact quantity of energy that The exact quantity of energy that it takes to remove the outermost it takes to remove the outermost electron from the atom.electron from the atom.

• Factors affecting Ionization Energy:Factors affecting Ionization Energy:

- nuclear charge- nuclear charge

- distance from the nucleus- distance from the nucleus

• Ionization energy increases across Ionization energy increases across the period ( left – right) due to the period ( left – right) due to increased nuclear chargeincreased nuclear charge

• Ionization energy decreases down Ionization energy decreases down the group ( top – bottom)the group ( top – bottom)

Trend of Atomic RadiusTrend of Atomic Radius

• Atomic size Atomic size is determined by how much is determined by how much space the electron takes up. It is also space the electron takes up. It is also depends on how far its valence electrons depends on how far its valence electrons are from the nucleus.are from the nucleus.

• The atom will be large if the electron is The atom will be large if the electron is far from the nucleusfar from the nucleus

- size increases down a group (top – - size increases down a group (top – bottom)bottom)

• The atom will be small if the electron The atom will be small if the electron is close to the nucleusis close to the nucleus

- size decreases across the period - size decreases across the period ( left – right)( left – right)

This is due to an increase in nuclear This is due to an increase in nuclear charge pulling them closer… the charge pulling them closer… the energy level stays the sameenergy level stays the same

Trend of Metallic/Non-Trend of Metallic/Non-Metallic PropertiesMetallic Properties

• Metallic properties: elements will Metallic properties: elements will form cations as they lose electrons form cations as they lose electrons (+ve charge)(+ve charge)

• Non-Metallic properties: elements Non-Metallic properties: elements form anions as they gain electrons (-form anions as they gain electrons (-ve charge)ve charge)

Trend of Melting / Boiling Trend of Melting / Boiling PointsPoints

• Melting and Boiling point increase Melting and Boiling point increase from the right side of the periodic from the right side of the periodic table until it reaches aluminum and table until it reaches aluminum and siliconsilicon

• Here, melting point and boiling point Here, melting point and boiling point then begin to decrease.then begin to decrease.

Trend of ReactivityTrend of Reactivity

How likely/vigorously an atom is to react How likely/vigorously an atom is to react with other substanceswith other substances

• Metals:Metals:- Period: decreases from left to rightPeriod: decreases from left to right- Group: increases down the groupGroup: increases down the group

The farther left and down you go the The farther left and down you go the easier it is for electrons to be taken easier it is for electrons to be taken away. (Higher Reactivity)away. (Higher Reactivity)

Trend of ReactivityTrend of Reactivity

• Non-MetalsNon-Metals- Period: increases from left to rightPeriod: increases from left to right- Group: decreases down the groupGroup: decreases down the group

The farther right and up you go the The farther right and up you go the higher electronegativity – vigorous higher electronegativity – vigorous exchange of electronsexchange of electrons

Classification of ElementsClassification of Elements

Elements can be classified into 4 Elements can be classified into 4 groups based on electrons.groups based on electrons.

1. 1. Noble gases:Noble gases: outermost s & p outermost s & p sublevels are filled. Belong to group 0. sublevels are filled. Belong to group 0. (Also called inert gases.)(Also called inert gases.)

2. 2. Representative elements: Representative elements: outermost outermost s or p sublevel is partially filleds or p sublevel is partially filled

33. . Transition metals:Transition metals: metallic elements in metallic elements in which the outermost s sublevel and near d which the outermost s sublevel and near d sublevel contain electrons. (Group B sublevel contain electrons. (Group B elements)elements)

4. 4. Inner transition metals:Inner transition metals: metallic metallic elements in which the outermost s sublevel elements in which the outermost s sublevel and nearby f sublevel generally contain and nearby f sublevel generally contain electrons. (Lanthanide & Actinide series)electrons. (Lanthanide & Actinide series)

1.1. Binary Ionic Compounds Binary Ionic Compounds (criss cross and reduce)(criss cross and reduce)

2. Binary Covalent Compounds (use 2. Binary Covalent Compounds (use the prefixes)the prefixes)

3. Acids (acid 3. Acids (acid rules)rules)

NOMENCLATURENOMENCLATURE: PROCESS USED : PROCESS USED FOR NAMING CHEMICAL COMPOUNDSFOR NAMING CHEMICAL COMPOUNDS

• Be able to balance and name Be able to balance and name formulas!formulas!

Chapter 2 Questions Chapter 2 Questions (p. 32-37)(p. 32-37)

# 24, 26, 32, 46, 50, 52, # 24, 26, 32, 46, 50, 52, 58, 60, 62, 64, 66, 68, 58, 60, 62, 64, 66, 68, 70, 72, 74, 78, 8770, 72, 74, 78, 87