Chemistry

ChemistryChemistry

Composition of MatterComposition of MatterEnergyEnergySolutionsSolutions

The Chemical The Chemical Context of LifeContext of Life

Composition of MatterComposition of Matter

MatterMatterElementsElementsAtomsAtomsCompoundsCompounds

Learning Learning ObjectivesObjectives

1.1. Define element, atom, Define element, atom, compound, & moleculecompound, & molecule

2.2. Draw a model of the structure of Draw a model of the structure of an atoman atom

3.3. Explain what determines an Explain what determines an atom’s stabilityatom’s stability

4.4. Contrast ionic & covalent bondsContrast ionic & covalent bonds

Elements, Atoms, & Elements, Atoms, & Chemical BondingChemical Bonding

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Composition of MatterComposition of Matter

• MatterMatter Anything that occupies space & Anything that occupies space &

has has massmass: : - - quantity of matter in an quantity of matter in an

objectobject• ElementElement::

A pure substance that cannot be A pure substance that cannot be broken down chemically into broken down chemically into simpler kinds of matter simpler kinds of matter

Periodic Table of the ElementsPeriodic Table of the ElementsElements of organic molecules

Important ions / metals

Trace elements

118 Discovered

Periodic Table:Periodic Table:Symbols & Numbers Symbols & Numbers

1

2

36

4

5

Atomic Number

Valence Electrons

Element Symbol

Element Name

Energy Shell

Atomic Mass #

Most Common Elements In Living

Tissues

Note: # e- matches # p+ Note: how e- fill energy levels

Elements of Living ThingsElements of Living Things

S P O N C HS P O N C H U H X I A YU H X I A Y L O Y T R DL O Y T R D F S G R B RF S G R B R U P E O O OU P E O O O R H N G N GR H N G N G O E EO E E R N NR N N UU SS

Atomic Structure: NucleusAtomic Structure: Nucleus

• AtomAtom:: The smallest particle of an element that The smallest particle of an element that

still retains all the properties of that still retains all the properties of that elementelement

• NucleusNucleus:: protonsprotons: : pp++

neutronsneutrons: : nn00

Proton / positive charge / plus sign

Neutron / neutral charge/ no sign

Atomic Structure & Atomic Structure & TerminologyTerminology

• Atomic NumberAtomic Number:: # of # of protonsprotons ( (pp++))

• Atomic Mass NumberAtomic Mass Number:: # of # of protonsprotons ( (pp++) + ) + # of # of neutronsneutrons

((nn00))

• Energy Levels (Shells)Energy Levels (Shells):: electronselectrons: : ee--

orbitalsorbitals: regions where electrons orbit : regions where electrons orbit the nucleusthe nucleus

e- in “highest “energy levels have the most energy

CompoundsCompounds

• CompoundCompound:: A pure substance made up of atoms of A pure substance made up of atoms of

2 or more elements in a fixed ratio2 or more elements in a fixed ratio

• Chemical ReactionsChemical Reactions:: Elements combine in ways that cause Elements combine in ways that cause

their atoms to become their atoms to become stablestable Chemical bonds are broken, atoms are Chemical bonds are broken, atoms are

rearranged, & new attachments are rearranged, & new attachments are formedformed

Why do atoms undergo Why do atoms undergo chemical reactions?chemical reactions?

• Atoms that haveAtoms that have unfilled outer unfilled outer energy levels energy levels form form bonds bonds with with other atoms to become other atoms to become stablestable

• H & He need H & He need 2 e2 e-- to fill outer shell to fill outer shell• C, O, N, P, S, Na, Ca, K, Cl, I, etc C, O, N, P, S, Na, Ca, K, Cl, I, etc

need need 8 e8 e-- to fill outer shellto fill outer shell

Chemical BondingChemical Bonding

• Covalent BondCovalent Bond:: SharingSharing of 1 or more pairs of electrons of 1 or more pairs of electrons

between atomsbetween atoms StrongStrong chemical bond: valence shells chemical bond: valence shells

mergemerge

Compounds & MoleculesCompounds & Molecules

• Kinds of CompoundsKinds of Compounds:: Ionic compoundsIonic compounds – ionic bonding – ionic bonding Molecular compoundsMolecular compounds – covalent – covalent

bondingbonding

• MoleculeMolecule: : Requires covalent bondingRequires covalent bonding

The simplest part of a substance that The simplest part of a substance that retains all the properties of that retains all the properties of that substance & exists in a free statesubstance & exists in a free state


• Ionic BondIonic Bond:: TransferTransfer of 1 or 2 e- from one atom to of 1 or 2 e- from one atom to

another forming ionsanother forming ions CationsCations are are ++; ; anionsanions are are -- Oppositely charged ions Oppositely charged ions attractattract one one

anotheranother WeakWeak chemical bond: valence shells chemical bond: valence shells

do not mergedo not merge

Ionic BondingIonic Bonding



Ionically Bonded Compounds form Crystal Lattices

Molecules & Compounds

Not all compounds are molecules

Not all molecules are compounds

Types of CompoundsTypes of Compounds

• Molecular compoundsMolecular compounds– Covalently bonded atomsCovalently bonded atoms

ExEx: : HH22OO (water) is a (water) is a molecular molecular compoundcompound consisting of consisting of HH & & OO in a 2:1 in a 2:1 ratioratio

• Ionic compoundsIonic compounds– Ionically bonded atomsIonically bonded atomsExEx: : NaClNaCl (table salt) is an (table salt) is an ionic ionic

compoundcompound consisting of consisting of NaNa & & ClCl in a in a 1:1 ratio1:1 ratio



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EnergyEnergy

Energy & MatterEnergy & Matter

Energy & Chemical ReactionsEnergy & Chemical Reactions


1.1. List the 3 states of matter, and List the 3 states of matter, and explain how matter can change stateexplain how matter can change state

2.2. Describe how energy changes are Describe how energy changes are involved in chemical reactionsinvolved in chemical reactions

3.3. Explain how enzymes affect Explain how enzymes affect chemical reactions in organismschemical reactions in organisms

4.4. Explain what a redox reaction isExplain what a redox reaction is

Energy & MatterEnergy & Matter

• EnergyEnergy:: The ability to do The ability to do workwork or cause change or cause change Forms of energy:Forms of energy:

Radiant energy (light)Radiant energy (light)Thermal energy (heat)Thermal energy (heat)Chemical energy (stored & usable)Chemical energy (stored & usable)Electrical energy (stored & usable)Electrical energy (stored & usable)Mechanical energyMechanical energy

One form of One form of energy can be convertedenergy can be converted to to another formanother form

• Free EnergyFree Energy:: The energy in a system The energy in a system availableavailable to do work to do work Biological systems are Biological systems are OPENOPEN systemssystems

Energy Conversion

Radiant Energy

Stored Chemical Energy

Usable Chemical Energy of ATP

< Heat >

Free EnergyFree Energy

Movementcross membrane

Chemicalbreakdown

Change in position

Work:Work:Closed & Open SystemsClosed & Open Systems

Energy in Living Things

Kinds of Work Done by Cells

States of MatterStates of Matter

• All atoms & molecules in any All atoms & molecules in any substance are in substance are in constant motionconstant motion ExceptionException – absolute zero = 0 – absolute zero = 0 ooK or -K or -

273 273 ooCC• The rate of motion determines the The rate of motion determines the

state of matterstate of matter:: SolidSolid LiquidLiquid GasGas

Three States of MatterThree States of MatterCoexist on EarthCoexist on Earth

Liquid

Gas

Solid

Phases (States)Phases (States)of Matterof Matter

• SolidsSolids:: Little particle motionLittle particle motion – vibrate in place w/ strong – vibrate in place w/ strong

mutual attractionmutual attraction Fixed volume & shapeFixed volume & shape

• LiquidsLiquids:: Moderate particle motionModerate particle motion – move freely w/ moderate – move freely w/ moderate

mutual attractionmutual attraction Fixed volume taking the shape of the containerFixed volume taking the shape of the container

• GasesGases:: Rapid particle motionRapid particle motion – move rapidly w/ little or no – move rapidly w/ little or no

mutual attractionmutual attraction Unfixed volume filling the container they occupyUnfixed volume filling the container they occupy

Phase Changes Phase Changes in Matterin Matter

Phase changes occur when thermal energy is added to or removed from the substance in its current phase.

EnergyEnergy& Chemical Reactions& Chemical Reactions

• ReactantsReactants:: Combine to form productsCombine to form products Left side of typical chemical equationLeft side of typical chemical equation

• ProductsProducts:: Formed from reactantsFormed from reactants Right side of typical chemical equationRight side of typical chemical equation

Chemical Reaction Chemical Reaction NotationNotation

AA + + BB ABABreactant + reactant --reactant + reactant --yieldsyields

productproduct

COCO22 + + HH22OO HH22COCO33

Reversible ReactionsReversible Reactions

AA + + BB ABAB

Equilibrium: the rate of formation of AB from A + B is equal to the rate of formation of A + B from AB.

COCO22 + + HH22OO HH22COCO33

EnergyEnergy& Chemical Reactions& Chemical Reactions

• Exergonic ReactionsExergonic Reactions:: Release energyRelease energy Can occur spontaneouslyCan occur spontaneously DecompositionDecomposition: : breakdown of more complex breakdown of more complex

molecules into simpler onesmolecules into simpler ones

• Endergonic ReactionsEndergonic Reactions:: Absorb energyAbsorb energy Do NOT occur spontaneouslyDo NOT occur spontaneously SynthesisSynthesis: : formation of more complex formation of more complex

molecules from simpler onesmolecules from simpler ones

Energy Transfer:Energy Transfer:Exergonic ReactionExergonic Reaction

CC66HH1212OO66 ++ 66OO2 2 (sugar) (sugar) (oxygen gas)(oxygen gas)

66COCO22 ++ 6 6HH22OO ++ EnergyEnergy (carbon (carbon (water)(water) (ATP)(ATP)

dioxide)dioxide)

Example: Cellular Respiration

Energy Transfer:Energy Transfer:Endergonic ReactionEndergonic Reaction

66COCO22 ++ 6 6HH22OO ++ Energy Energy (carbon (carbon (water)(water) (from sunlight)(from sunlight)

dioxide)dioxide)

CC66HH1212OO66 ++ 66OO22

(sugar) (sugar) (oxygen gas)(oxygen gas)

Example: Photosynthesis

Energy Flow Energy Flow & Chemical Cycling& Chemical Cycling

Activation EnergyActivation Energy

• Activation EnergyActivation Energy:: Amount of energy needed to begin Amount of energy needed to begin

any chemical reactionany chemical reaction Necessary for both exergonic & Necessary for both exergonic &

endergonic reactionsendergonic reactions Used to break bonds in the reactants Used to break bonds in the reactants

so that new bonds can form to make so that new bonds can form to make the productsthe products

Reaction Energy ProfileReaction Energy ProfileActivation energy

Activation Energy Barrier Activation Energy Barrier & Enzymes& Enzymes

• CatalystCatalyst:: Chemical substances that Chemical substances that reducereduce the the

amount of activation energy needed amount of activation energy needed for a reaction to occurfor a reaction to occur

• EnzymesEnzymes:: Catalyst proteinsCatalyst proteins in living things in living things SpecificSpecific for particular chemical for particular chemical

reactionsreactions

Enzyme FunctionEnzyme Function

Chemical Reactions & Chemical Reactions & EnergyEnergy


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Enzymes & Activation Enzymes & Activation EnergyEnergy


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Reduction – Oxidation:Reduction – Oxidation:Redox ReactionsRedox Reactions

• ReductionReduction = = gaingain of e of e--

the reduced molecule is an oxidizing the reduced molecule is an oxidizing agentagent

electron acceptorelectron acceptor

• OxidationOxidation = = lossloss of e of e--

the oxidized molecule is a reducing the oxidized molecule is a reducing agentagent

electron donorelectron donor

Redox ReactionRedox Reaction

XX-2e-2e- + + YY XX + + YY-2e-2e-

Transfer of ElectronsTransfer of Electrons& Energy Release& Energy Release

2

Energy & The Chemistry of Energy & The Chemistry of LifeLife



SolutionsSolutions

Describing SolutionsDescribing Solutions

Acids & BasesAcids & Bases


1.1. Define solution, solute, & Define solution, solute, & concentrationconcentration

2.2. Explain the dissociation of waterExplain the dissociation of water

3.3. Contrast the properties of acids Contrast the properties of acids & bases& bases

4.4. Explain the action of buffersExplain the action of buffers

Describing SolutionsDescribing Solutions

• A A solutionsolution consists of a consists of a solutesolute dissolved in a dissolved in a solventsolvent

• In In aqueous solutionsaqueous solutions, the solvent , the solvent is is waterwater

• ConcentrationConcentration:: The measurement of the amount of The measurement of the amount of

solute dissolved in a fixed amount solute dissolved in a fixed amount of solventof solvent

• In a In a saturated solutionsaturated solution, no more , no more solute can dissolvesolute can dissolve

• Water is polar & can dissolve other substances

Dissociation of WaterDissociation of Water

HH2OO HH+ + + OHOH-

hydrogen hydroxidehydrogen hydroxide

ion ion ion ion

This equation can be simplified by “removing” a water molecule from each

side of the reaction.

HH2O + HO + H2OO HH3O+ + + OHOH-


•AcidAcid:: Any substance that Any substance that

donates Hdonates H+ to a solutionto a solution

•BaseBase:: Any substance that Any substance that

absorbs Habsorbs H+ from a from a solutionsolution


•AcidityAcidity:: Common acidic foodsCommon acidic foods: citrus : citrus

fruits; coffee & tea; vinegar; fruits; coffee & tea; vinegar; tomatoes; peppers tomatoes; peppers

•AlkalinityAlkalinity:: Common alkaline foodsCommon alkaline foods: milk; : milk;

cheese; sardines; salmon; eggs; cheese; sardines; salmon; eggs; chocolate; yogurt; soy beans; chocolate; yogurt; soy beans; cauliflowercauliflower

AcidsAcids

•Acid FormationAcid Formation::

HCl HCl HH++ + Cl + Cl--

AcidicAcidic solutions solutions::SourSour taste tasteCorrosiveCorrosive to many to many materialsmaterials

BasesBases

•Base FormationBase Formation::

NaOH NaOH OHOH-- + Na + Na++

AlkalineAlkaline solutions solutions::BitterBitter taste tasteSlipperySlippery to touch to touch

pH: Relative HpH: Relative H+ (H (H33OO++) Ion ) Ion ConcentrationConcentration

[H[H33OO+] = [OH] = [OH-] ] neutralneutral solution solution pH 7.00pH 7.00[H[H33OO+] > [OH] > [OH-] ] acidacid solution solution pH 0 – 6.99pH 0 – 6.99[H[H33OO+] < [OH] < [OH-] ] basebase solution solution pH 7.01 – 14pH 7.01 – 14

Note:Note: HH33OO++ & & HH++ represent the same represent the same thing.thing.

Acid Conditions Alkaline ConditionsNeutral

Condition

Intestinal Fluid

Pancreatic juice

The pH Scale is The pH Scale is LogarithmicLogarithmic

• A change of 1 pH number = a A change of 1 pH number = a 10-fold 10-fold change in Hchange in H++ concentration concentration

• ExEx: a pH of 3 is 10X more acidic than a : a pH of 3 is 10X more acidic than a pH of 4pH of 4

• Q:Q: A solution has a pH of 5. What A solution has a pH of 5. What would be the new pH of this solution if would be the new pH of this solution if we increased the Hwe increased the H++ conc. by 1,000 conc. by 1,000 times?times?

• Q:Q: By what amount would the H By what amount would the H++ conc. conc. need to be reduced to move the pH of need to be reduced to move the pH of a solution from 4 to 10?a solution from 4 to 10?

BuffersBuffers

• A A weak acidweak acid & a & a saltsalt of that acid of that acid• In most biological systems:In most biological systems:

Weak acid: Weak acid: carbonic acidcarbonic acid

HH2COCO3

Salt: Salt: sodium bicarbonatesodium bicarbonate

NaHCONaHCO3

Buffer ActivityBuffer Activity

• Substances that Substances that stabilize the pH of stabilize the pH of a solutiona solution by removing or adding by removing or adding HH+

Remove HRemove H+ under acidic conditions under acidic conditions Add HAdd H+ under alkaline (basic) under alkaline (basic)

conditionsconditions

• Maintain physiological pHMaintain physiological pH

Removal of HRemoval of H+

Dissociation of sodium bicarbonateDissociation of sodium bicarbonate:: NaHCONaHCO3 HCOHCO3

- ++ NaNa+

Association of HAssociation of H+ w/ carbonate w/ carbonate:: (from acid)(from acid) HH+ ++ HCOHCO3

- HH2COCO3

Dissociation of carbonic acidDissociation of carbonic acid::HH2COCO3 HH200 ++ COCO2

Removal of OHRemoval of OH-

Dissociation of carbonic acidDissociation of carbonic acid::H2COCO3 HH+ + + HCOHCO3

-

Association of OHAssociation of OH- w/ H w/ H+::(from base)(from base) OH OH- ++ HH+ HH2OO

Carbonic Acid Video

Mixtures & SolutionsMixtures & Solutions


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