Basic Chemistry ReviewBasic Chemistry Review

MatterMatter

1. Matter refers to anything that takes up 1. Matter refers to anything that takes up space and has massspace and has mass

2. All matter (living and nonliving) is 2. All matter (living and nonliving) is composed of basic elementscomposed of basic elements a. Elements cannot be broken down to a. Elements cannot be broken down to

substances with different chemical or physical substances with different chemical or physical propertiesproperties

b. There are 92 naturally occurring elementsb. There are 92 naturally occurring elements c. Six elements (C, H, N, O, P, S) make up 98% of c. Six elements (C, H, N, O, P, S) make up 98% of

most organismsmost organisms

Elements Contain AtomsElements Contain Atoms

1. Chemical and physical properties of atoms depend on 1. Chemical and physical properties of atoms depend on the subatomic particles:the subatomic particles:

a. Different atoms contain specific numbers of protons, a. Different atoms contain specific numbers of protons, neutrons, and electronsneutrons, and electrons

b. Protons (+ charge) and neutrons (neutral charge) are in b. Protons (+ charge) and neutrons (neutral charge) are in nucleus of atoms; electrons (- charge) move around nucleusnucleus of atoms; electrons (- charge) move around nucleus

2. Isotopes = atoms with the same number of protons but 2. Isotopes = atoms with the same number of protons but differ in number of neutrons; e.g., a carbon atom has six differ in number of neutrons; e.g., a carbon atom has six protons but may have more or less than usual six neutronsprotons but may have more or less than usual six neutrons

a. Isotopes used to determine age of fossils and in medical a. Isotopes used to determine age of fossils and in medical diagnostic and treatment procedures diagnostic and treatment procedures

Chemical Properties of Chemical Properties of AtomsAtoms

1. Since protons are positively charged & electrons 1. Since protons are positively charged & electrons are negatively charged they are attracted to each are negatively charged they are attracted to each otherother

2. Arrangement of atom's electrons is determined by 2. Arrangement of atom's electrons is determined by total number of electrons and electron shell they total number of electrons and electron shell they occupyoccupy

a. Energy = capacity to do worka. Energy = capacity to do work

b. Electrons with least amount of potential energy are located b. Electrons with least amount of potential energy are located in shell closest to nucleus; electrons having more potential in shell closest to nucleus; electrons having more potential energy are located in shells farther from nucleus energy are located in shells farther from nucleus

c. How atoms react with one another is dependent upon c. How atoms react with one another is dependent upon number of electrons in outer shellnumber of electrons in outer shell

1) Atoms with filled outer shells do not react with other 1) Atoms with filled outer shells do not react with other atomsatoms

2) In atom with one shell, outer shell is filled when it 2) In atom with one shell, outer shell is filled when it contains two electronscontains two electrons

3) For atoms with more than one shell, the outer shell is 3) For atoms with more than one shell, the outer shell is stable when it contains eight electrons stable when it contains eight electrons

4) Atoms with unfilled outer shells react with other atoms 4) Atoms with unfilled outer shells react with other atoms so each has stable outer shellso each has stable outer shell

5) Atoms can give up, accept, or share electrons in order to 5) Atoms can give up, accept, or share electrons in order to have a stable outer shellhave a stable outer shell

Atoms form Molecules and Atoms form Molecules and CompoundsCompounds

A. Molecules = two or more atoms of A. Molecules = two or more atoms of same or different elements bonded same or different elements bonded together (e.g., Otogether (e.g., O22))

B. Compound = molecule of two or B. Compound = molecule of two or more different elements bonded more different elements bonded together (e.g., Htogether (e.g., H22O)O)

Types of BondsTypes of Bonds

1. 1. CovalentCovalent bond - involves bond - involves sharingsharing of of electron(s). Electrons possess energy; bonds that electron(s). Electrons possess energy; bonds that exist between atoms in molecules contain exist between atoms in molecules contain energyenergy..

Sharing of a pair of electrons creates a single bond Sharing of a pair of electrons creates a single bond represented by single dash, e.g. water Hrepresented by single dash, e.g. water H22O is made of O is made of two single bonds H-O-H. Sharing two pairs of electrons is two single bonds H-O-H. Sharing two pairs of electrons is represented by two dashes, C=Crepresented by two dashes, C=C

Know the number of covalent bonds each of the six most Know the number of covalent bonds each of the six most important elements can form.important elements can form.

Element# of covalent bonds:Hydrogen-1, Oxygen-Element# of covalent bonds:Hydrogen-1, Oxygen-2, Nitrogen-3, Carbon-4, Phosphorous-5, Sulfur-22, Nitrogen-3, Carbon-4, Phosphorous-5, Sulfur-2

Types of bondsTypes of bonds

2. 2. IonicIonic bond - electrons are bond - electrons are transferredtransferred from from one atom to another, e.g. salt NaClone atom to another, e.g. salt NaCl

3. 3. HydrogenHydrogen bond - bond - weakweak attractive force attractive force between slightly positive hydrogen atom of one between slightly positive hydrogen atom of one molecule and slightly negative atom in another or molecule and slightly negative atom in another or the same moleculethe same molecule

a. E.X.: in a water molecule the electrons spend more a. E.X.: in a water molecule the electrons spend more time orbiting the oxygen than the hydrogens, therefore time orbiting the oxygen than the hydrogens, therefore the oxygen becomes slightly negative and the two the oxygen becomes slightly negative and the two hydrogens become slightly positivehydrogens become slightly positive

b. Such polar molecules attract each other like magnetsb. Such polar molecules attract each other like magnets

Oxidation - reduction:Oxidation - reduction:

1. 1. OxidationOxidation =  the loss of electrons (or =  the loss of electrons (or loss of hydrogen atoms), a molecule that loss of hydrogen atoms), a molecule that loses an electron is oxidizedloses an electron is oxidized

2. 2. ReductionReduction = the gain of electrons (or = the gain of electrons (or gain of hydrogen atoms), a molecule gain of hydrogen atoms), a molecule that gains an electron is reducedthat gains an electron is reduced

WaterWater

A. Life evolved in waterA. Life evolved in water All living things are 70-90% waterAll living things are 70-90% water

Because water is a polar molecule, water Because water is a polar molecule, water molecules are hydrogen bonded to each othermolecules are hydrogen bonded to each other

a. a. hydrophilic moleculeshydrophilic molecules - polar molecules - polar molecules attracted to water molecules attracted to water molecules

b. b. hydrophobic moleculehydrophobic molecules - non-polar molecules s - non-polar molecules repelled by water repelled by water

Properties of WaterProperties of Water

1. Water 1. Water resists temperature changesresists temperature changes because hydrogen because hydrogen bonds between water molecules require a large amount of heat bonds between water molecules require a large amount of heat to breakto break

a. Calorie = amount of heat energy required to raise temperature a. Calorie = amount of heat energy required to raise temperature of one gram of water 1° C. This is about twice that of other liquidsof one gram of water 1° C. This is about twice that of other liquids

b. Water has a high heat of vaporization - takes 540 calories to b. Water has a high heat of vaporization - takes 540 calories to change water to a gaschange water to a gas

c. When animals sweat, evaporation of the sweat takes away body c. When animals sweat, evaporation of the sweat takes away body heat, thus cooling the animal heat, thus cooling the animal

d. Because water resists temperature changes the earth's surface d. Because water resists temperature changes the earth's surface temperature is moderate and organisms are protected from rapid temperature is moderate and organisms are protected from rapid temperature changes, this helps them maintain normal temperature changes, this helps them maintain normal temperatures temperatures

2. Water is 2. Water is universal solventuniversal solvent, , facilitates chemical reactions both facilitates chemical reactions both outside of and within living systemsoutside of and within living systems a. Water is a universal solvent because it a. Water is a universal solvent because it

dissolves a great number of solutesdissolves a great number of solutes

b. Important because living organisms get b. Important because living organisms get and transport most of needed chemicals and transport most of needed chemicals in water or water based solutionsin water or water based solutions

3. Water molecules are cohesive and adhesive3. Water molecules are cohesive and adhesive CohesionCohesion - like molecules cling to each other - like molecules cling to each other

AdhesionAdhesion - ability to adhere to polar surfaces; water - ability to adhere to polar surfaces; water molecules have positive, negative poles.molecules have positive, negative poles.

CapillarityCapillarity - the tendency for a liquid to move upward against - the tendency for a liquid to move upward against pull of gravity through a narrow space, e.g. water rises up tree pull of gravity through a narrow space, e.g. water rises up tree from roots to leaves through small tubesfrom roots to leaves through small tubes

1) Adhesion of water to walls of vessels prevents water column 1) Adhesion of water to walls of vessels prevents water column from breaking apartfrom breaking apart

2) Cohesion allows evaporation from leaves to pull water column 2) Cohesion allows evaporation from leaves to pull water column from rootsfrom roots

4. Frozen water is 4. Frozen water is less denseless dense than liquid than liquid water water  a. Below 4° C, hydrogen bonding becomes more a. Below 4° C, hydrogen bonding becomes more

rigid but open, causing expansionrigid but open, causing expansion

b. Because ice is less dense, it floats; therefore, b. Because ice is less dense, it floats; therefore, bodies of water freeze from the top downbodies of water freeze from the top down

c. This means that ice floats and the bottoms of c. This means that ice floats and the bottoms of

lakes and oceans are still available for life and lakes and oceans are still available for life and also insulated during cold weather also insulated during cold weather

Acids and BasesAcids and Bases

1. Water dissociates - has a tendency to 1. Water dissociates - has a tendency to spontaneously break into hydrogen and hydroxide spontaneously break into hydrogen and hydroxide ions:ions: HH220 ---> H+ (hydrogen) + OH- (hydroxide)0 ---> H+ (hydrogen) + OH- (hydroxide)

2. 2. AcidAcid molecules dissociate in water, releasing molecules dissociate in water, releasing hydrogen ions (H+) ions: hydrogen ions (H+) ions:  Hydrochloric acid (HCl) is a strong acid: HCl ---> H+ + Cl Hydrochloric acid (HCl) is a strong acid: HCl ---> H+ + Cl

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3. 3. BasesBases are molecules that take up hydrogen are molecules that take up hydrogen ions or release hydroxide ions:ions or release hydroxide ions: Sodium hydroxide (NaOH) is a strong base: NaOH ---> Sodium hydroxide (NaOH) is a strong base: NaOH --->

Na+ + OH-Na+ + OH-

4. pH scale, which ranges from 0 to 14, is used to indicate the 4. pH scale, which ranges from 0 to 14, is used to indicate the strength of acids and basesstrength of acids and bases

a. pH = a measure of hydrogen (H+) ion concentration in a solutiona. pH = a measure of hydrogen (H+) ion concentration in a solution

b. Low pH value indicates a high concentration of H+ ions (acids)b. Low pH value indicates a high concentration of H+ ions (acids)

c. High pH value indicates a low concentration of H+ ions (bases)c. High pH value indicates a low concentration of H+ ions (bases)

d. pH value of 7 is neutral, i.e. the solution has an equal concentration d. pH value of 7 is neutral, i.e. the solution has an equal concentration of H+ and OH- ionsof H+ and OH- ions

e. pH scale is e. pH scale is logarithmiclogarithmic, i.e. a ten fold difference for each number, i.e. a ten fold difference for each number

E.X.: pH 4 is 10 times more acidic than 5, and 100 times more E.X.: pH 4 is 10 times more acidic than 5, and 100 times more acidic than 6acidic than 6

5. Buffers keep pH steady and within normal 5. Buffers keep pH steady and within normal limits in living organisms, e.g. blood pH is limits in living organisms, e.g. blood pH is 7.47.4

a. Buffers stabilize pH of a solution by taking up a. Buffers stabilize pH of a solution by taking up excess hydrogen or hydroxide ions excess hydrogen or hydroxide ions

b. Carbonic acid helps keep blood pH within b. Carbonic acid helps keep blood pH within normal limitsnormal limits

  

SaltsSalts

Any compound that results from the Any compound that results from the chemical interaction of an acid and a chemical interaction of an acid and a basebase

Dissociate in solution to become ionsDissociate in solution to become ions

See common salts on page 47See common salts on page 47

SolutionsSolutions ColloidsColloids SuspensionsSuspensions

Homogeneous Heterogeneous Heterogeneous

Particle size:  0.01 - 1 nm; can be atoms, ions, molecules

Particle size:  1 - 1000 nm, dispersed; can be aggregates or large molecules

Particle size:  over 1000 nm, suspended; can be large particles or aggregates

Do not separate on standingDo not separate on standing

Particles settle out

Cannot be separated by filtration

Cannot be separated by filtration

Can be separated by filtration

Do not scatter lightScatter light (Tyndall effect)

May scatter light, but are not transparent

Organic SubstancesOrganic Substances

CarbohydratesCarbohydrates Provide energy that cells requireProvide energy that cells require Contribute to cell structureContribute to cell structure Built by simple sugar molecules Built by simple sugar molecules

(monosaccharides)(monosaccharides)

Lipids (Fat, Phospholipids, Steroids)Lipids (Fat, Phospholipids, Steroids)

Supply energy, build cell partsSupply energy, build cell parts

Basic building block of fat molecules is Basic building block of fat molecules is combination of glycerol and fatty acidscombination of glycerol and fatty acids

ProteinProtein Serve as structural materials, energy sources, hormones, cell Serve as structural materials, energy sources, hormones, cell

surface receptors, and enzymessurface receptors, and enzymes

Enzymes speed chemical reactions without being consumedEnzymes speed chemical reactions without being consumed

Amino acids are building blocks of proteinsAmino acids are building blocks of proteins

Proteins vary in the number and types of amino acids contained Proteins vary in the number and types of amino acids contained and in their sequenceand in their sequence

Amino acid chain of protein folds into a complex shape that is Amino acid chain of protein folds into a complex shape that is maintained by hydrogen bondsmaintained by hydrogen bonds

Excessive heat, radiation, electricity, altered pH, or chemicals can Excessive heat, radiation, electricity, altered pH, or chemicals can alter proteinsalter proteins

Nucleic AcidsNucleic Acids Nitrogen base, pentose sugar, phosphate)Nitrogen base, pentose sugar, phosphate) Genetic material and control cellular activitiesGenetic material and control cellular activities Nucleic acid molecules composed of Nucleic acid molecules composed of

mucleotides:mucleotides: Adenine AAdenine A Guanine GGuanine G Cytosine CCytosine C Uracil UUracil U Thymine TThymine T

A & G are purines (large 2 ring bases)A & G are purines (large 2 ring bases) C, U, & T are pyrimidines (small single ring bases)C, U, & T are pyrimidines (small single ring bases)

Important Nucleic AcidsImportant Nucleic Acids

DNA (deoxyribonucleic acid)DNA (deoxyribonucleic acid) Double stranded polymer (double helix)-Double stranded polymer (double helix)-

twisted laddertwisted ladder Nucleotides building are A, G, C, and TNucleotides building are A, G, C, and T Pentose sugar is deoxyribosePentose sugar is deoxyribose Stores information that cell parts use to Stores information that cell parts use to

construct specific protein molecules construct specific protein molecules “Blueprint”“Blueprint”

Nucleotides held by hydrogen bondsNucleotides held by hydrogen bonds A always bonds to TA always bonds to T G always bonds to CG always bonds to C

RNA (ribonucleic acid)RNA (ribonucleic acid) Help synthesize proteinHelp synthesize protein Pentose sugar is ribosePentose sugar is ribose Single strands of nucleotidesSingle strands of nucleotides

A, G, C, & U (U replaces T)A, G, C, & U (U replaces T) A always bonds to UA always bonds to U G always bonds to CG always bonds to C

Three types of RNAThree types of RNA

Transfer RNA (tRNA)Transfer RNA (tRNA) Small & clover leaf shapedSmall & clover leaf shaped Translate messages from mRNATranslate messages from mRNA

Messenger RNA (mRNA)Messenger RNA (mRNA) Long nucleotides that resemble half-Long nucleotides that resemble half-

DNA moleculesDNA molecules Carry messages from DNA for building a Carry messages from DNA for building a

polypeptide (amino acid chain)polypeptide (amino acid chain)

Ribosomal RNA (rRNA)Ribosomal RNA (rRNA) Forms ribosomes (site of protein Forms ribosomes (site of protein

synthesis)synthesis) Nucleolar organizerNucleolar organizer