CHAPTER 6 – CHAPTER 6 – THE THE CHEMISTRY CHEMISTRY OF OF LIFE LIFE SECTION 6.1 – Atoms + SECTION 6.1 – Atoms + their Interactions their Interactions p. 141-151 p. 141-151
Dec 26, 2015
CHAPTER 6 – CHAPTER 6 – THETHE CHEMISTRYCHEMISTRY OFOF LIFELIFE
SECTION 6.1 – Atoms + SECTION 6.1 – Atoms + their Interactionstheir Interactions
p. 141-151p. 141-151
AtomsAtoms: The Building Blocks of : The Building Blocks of Rocks - and You…Rocks - and You…
Both living and nonliving things are Both living and nonliving things are composed of the basic building composed of the basic building blocks called blocks called ATOMSATOMS
ElementsElements DefinitionDefinition
A substance that can’t be broken down A substance that can’t be broken down into simpler chemical substancesinto simpler chemical substances
Examples:Examples: GoldGold TungstenTungsten HeliumHelium
ElementsElements Only about Only about 2525 elements are essential elements are essential
to living thingsto living things Four make up Four make up 96%96% of a human body: of a human body:
CarbonCarbon HydrogenHydrogen OxygenOxygen NitrogenNitrogen
ElementsElements Elements are Elements are
identified by a identified by a symbolsymbol C – CarbonC – Carbon Ca – CalciumCa – Calcium
Trace elementsTrace elements Elements present in Elements present in
small amounts in small amounts in living thingsliving things
Examples:Examples: IronIron CopperCopper ZincZinc IodineIodine
AtomsAtoms: The Building Blocks of : The Building Blocks of ElementsElements
DefinitionDefinition The smallest particle of an element that The smallest particle of an element that
has the characteristics of that elementhas the characteristics of that element Basic building block of all matterBasic building block of all matter
AtomAtom - Structure - Structure NucleusNucleus
Center of the atomCenter of the atom Contains:Contains:
ProtonsProtons Positively charged Positively charged
particles (pparticles (p++)) NeutronsNeutrons
Particles with no Particles with no charge (ncharge (n00))
Nucleus has a Nucleus has a positivepositive charge charge
AtomAtom - Structure - Structure Elements differ in the number of Elements differ in the number of
protonsprotons each has each has Example:Example:
Iron vs. AluminumIron vs. Aluminum
AtomAtom - Structure - Structure ElectronsElectrons
Small, negatively charged particles that Small, negatively charged particles that surround the nucleus (esurround the nucleus (e--))
Held in place by its attraction to pHeld in place by its attraction to p++ in nucleus in nucleus Found in Found in electronelectron cloudsclouds
# electrons is energy levels# electrons is energy levels 11stst – 2 – 2 22ndnd – 8 – 8 33rdrd – 18 – 18
Electron energy levelsElectron energy levels
IsotopesIsotopes DefinitionDefinition
Atoms of the same element that have Atoms of the same element that have different numbers of neutronsdifferent numbers of neutrons
Examples:Examples: C-12C-12 C-13C-13 C-14C-14
IsotopesIsotopes Uses of isotopes:Uses of isotopes:
Some are Some are radioactiveradioactive and therefore can and therefore can be used in be used in radiation treatmentsradiation treatments
Can be used to estimate age of objects Can be used to estimate age of objects ((radioactive datingradioactive dating))
Compounds + BondingCompounds + Bonding CompoundCompound
A substance composed of atoms of two A substance composed of atoms of two or more different elements that is or more different elements that is chemically combinedchemically combined
Example:Example: TABLE SALT - TABLE SALT - NaClNaCl
Most elements in Most elements in nature are found in nature are found in compoundscompounds Atoms combine with Atoms combine with
other atoms to become other atoms to become stablestable
Outermost energy level Outermost energy level is filledis filled
Is this atom stable?Is this atom stable?
Compounds + BondingCompounds + Bonding
Types of BondsTypes of Bonds CovalentCovalent
When two or more atoms share When two or more atoms share electronselectrons
Example:Example:
Hydrogen, HHydrogen, H22
Most compounds in organisms have Most compounds in organisms have covalent bondscovalent bonds
Sugars, fats, proteins, + waterSugars, fats, proteins, + water
Types of BondsTypes of Bonds MoleculeMolecule
A group of atoms held together by a A group of atoms held together by a covalent bondcovalent bond
Example:Example: WATER WATER
Types of BondsTypes of Bonds Ionic bondIonic bond
The attractive force between two ions of The attractive force between two ions of opposite chargeopposite charge
Formed by combining Formed by combining ionsions – a charged – a charged particle made of atomsparticle made of atoms
Opposites attract – “+” like “-”Opposites attract – “+” like “-” Example:Example:
Table SaltTable Salt
How an Ionic bond forms…How an Ionic bond forms…
Chemical ReactionsChemical Reactions Occurs when bonds are Occurs when bonds are formedformed or or
brokenbroken, causing substances to , causing substances to recombine into different substancesrecombine into different substances
Occurs within Occurs within cellscells MetabolismMetabolism
All the chemical reactions that occur All the chemical reactions that occur within an organismwithin an organism
Chemical ReactionsChemical Reactions Chemical reactions are represented Chemical reactions are represented
by writing by writing CHEMICALCHEMICAL EQUATIONSEQUATIONS Example – the formation of waterExample – the formation of water 22 HH22 + + 11OO22 22 HH22OO
ReactantsReactants ProductsProducts CoefficientsCoefficients
Indicates the # of moleculesIndicates the # of molecules SubscriptsSubscripts
Indicates the # of atomsIndicates the # of atoms Equations must be Equations must be BALANCEDBALANCED!!!!!!
Mixtures + SolutionsMixtures + Solutions MixtureMixture
A combination of substances in which A combination of substances in which the individual components retain their the individual components retain their own propertiesown properties
Example:Example: Sugar + WaterSugar + Water Trail MixTrail Mix
SolutionsSolutions DefinitionDefinition
A mixture in which one A mixture in which one or more substances or more substances are distributed evenly are distributed evenly in anotherin another
Parts:Parts: Solute Solute
Substance that gets Substance that gets dissolveddissolved
SolventSolvent Substance doing the Substance doing the
dissolvingdissolving
ConcentrationConcentration DefinitionDefinition
Amount of solute Amount of solute dissolved in fixed dissolved in fixed amount of solventamount of solvent
The more solute The more solute dissolved in the dissolved in the solvent, the greater solvent, the greater the concentration of the concentration of the solutionthe solution
Acids + BasesAcids + Bases Chemical reactions can occur only Chemical reactions can occur only
when conditions are rightwhen conditions are right A reaction may depend upon:A reaction may depend upon:
Available energyAvailable energy TemperatureTemperature Concentration of substanceConcentration of substance pHpH
Acids + BasesAcids + Bases pHpH
A measure of how acidic or basic a A measure of how acidic or basic a solution issolution is
Scale ranges from 0 to 14Scale ranges from 0 to 14
Acids + BasesAcids + Bases AcidAcid
Substance that forms HSubstance that forms H++ ions in water ions in water pH range – below 7pH range – below 7 Typically sour to taste; can be corrosive Typically sour to taste; can be corrosive Examples:Examples:
LemonLemon TomatoTomato Stomach acidStomach acid
Acids + BasesAcids + Bases NeutralNeutral
Substance that has pH value = 7Substance that has pH value = 7 Example:Example:
Pure waterPure water
Acids + BasesAcids + Bases BaseBase
Substance that forms hydroxide ions Substance that forms hydroxide ions (OH(OH--) in water) in water
pH range – above 7pH range – above 7 Typically bitter to taste; feels slipperyTypically bitter to taste; feels slippery Examples:Examples:
EggEgg Drain cleanerDrain cleaner AntacidAntacid