Mr. Hunter BiologyMr. Hunter Biology10/18/201210/18/2012

• Objective(s)Objective(s)• SWBATSWBAT• Identify the properties of an acid and a baseIdentify the properties of an acid and a base• Analyze the pH scaleAnalyze the pH scale• Determine the properties of buffersDetermine the properties of buffers• Analyze the parts of a chemical reaction and Analyze the parts of a chemical reaction and

enzymesenzymes• Bell Ringer: Bell Ringer: How many more times acidic is stomach How many more times acidic is stomach

acid than urine? Pg. 44 pH scaleacid than urine? Pg. 44 pH scale

Bell RingerBiology 10/17/2012

• What is causing the two portions of the solution not to mix together?

• Explain your answer.

Chemistry Overview and the Properties Chemistry Overview and the Properties of Waterof Water

Mr. HunterMr. HunterBiologyBiology

Kennedy High SchoolKennedy High School10/12/201110/12/2011

Nature of MatterNature of Matter• MatterMatter: Anything that has : Anything that has

mass and occupies spacemass and occupies space• All matter is made of atomsAll matter is made of atoms• AtomAtom: The smallest unit of : The smallest unit of

matter that cannot be matter that cannot be broken down by chemical broken down by chemical processes.processes.

• Parts of an atomParts of an atom: nucleus, : nucleus, neutrons, protons and neutrons, protons and electronselectrons

• Question: What are the Question: What are the major parts of an atom?major parts of an atom?

Nature of MatterNature of Matter

• ElementElement: Substance made of : Substance made of one kind of atom – pure one kind of atom – pure substancesubstance

• Each element is represented by Each element is represented by a one or two letter symbol. Ex. a one or two letter symbol. Ex. Na, Cl, He, H etc.Na, Cl, He, H etc.

• Each element differs by the Each element differs by the number of protons in the atom.number of protons in the atom.

• ElectronsElectrons help to form chemical help to form chemical bonds between atoms of bonds between atoms of different elementsdifferent elements

• Question: How do elements Question: How do elements differ from one another?differ from one another?

• Question: What are the Question: What are the functions of electrons?functions of electrons?

Nature of Matter and Nature of Matter and Chemical BondsChemical Bonds

• Covalent BondsCovalent Bonds: Sharing of electrons to : Sharing of electrons to form a molecule such as water.form a molecule such as water.

• Hydrogen bondsHydrogen bonds: found in water : found in water molecules. Shared electrons with molecules. Shared electrons with hydrogen and oxygen.hydrogen and oxygen.

• Unequal sharing of electronsUnequal sharing of electrons. Oxygen . Oxygen pulls electrons more than other elements. pulls electrons more than other elements. – – Polar substance –found in waterPolar substance –found in water

• Ionic Bond: Ionic Bond: Bonds between atoms that Bonds between atoms that have gained or loss more than one have gained or loss more than one electron. Ex. Na+ and Cl- = NaClelectron. Ex. Na+ and Cl- = NaCl

• Question: How are the electrons arranged Question: How are the electrons arranged in polar substances?in polar substances?

• Question: What is the difference between Question: What is the difference between covalent bonds and ionic bonds?covalent bonds and ionic bonds?

Water and PropertiesWater and Properties

• 70% of your body is water70% of your body is water• WaterWater is able to store heat is able to store heat

very efficiently. It can heat very efficiently. It can heat very slowly and retain heat very slowly and retain heat longer than any other longer than any other substance.substance.

• Heat Heat can be released from can be released from an object via water an object via water evaporation.evaporation.

• Question: How can an Question: How can an organism lower its body organism lower its body temperature?temperature?

Water and IceWater and Ice• The atoms in liquid water The atoms in liquid water

and free to move around.and free to move around.• The atoms of the elements The atoms of the elements

found in ice are rigid and found in ice are rigid and less dense than those less dense than those found in water.found in water.

• Therefore ice can float.Therefore ice can float.• Question: How do the Question: How do the

arrangement of molecules arrangement of molecules in ice and liquid water in ice and liquid water differ from each other?differ from each other?

Temperature ModerationTemperature Moderation• Water has a Water has a high heat high heat

capacity.capacity.• Water can Water can absorb absorb or or

release relatively large release relatively large amounts of heat with amounts of heat with only only slight changes in slight changes in temperaturetemperature..

• This property is due to This property is due to hydrogen bondinghydrogen bonding

Temperature ModerationTemperature Moderation• EnergyEnergy must be must be

absorbed absorbed to to breakbreak hydrogen bondshydrogen bonds• EnergyEnergy is is releasedreleased as as

heat heat when when hydrogen hydrogen bonds bonds are are formedformed..

• Question(s): Question(s): What must be What must be absorbed in order for hydrogen absorbed in order for hydrogen bonds to break?bonds to break?

• What must be released when What must be released when hydrogen bonds form?hydrogen bonds form?

Temperature ModerationTemperature Moderation• Energy that water absorbs Energy that water absorbs

is initially used to is initially used to break break hydrogen bonds between hydrogen bonds between molecules.molecules.

• When the bonds are When the bonds are broken the energy broken the energy increases the molecular increases the molecular motion of the molecules motion of the molecules which which causes the causes the temperature of the water temperature of the water to increase.to increase.

Temperature ModerationTemperature Moderation• When the When the

temperaturetemperature of water of water dropsdrops, , hydrogen hydrogen bonds reformbonds reform, which , which releasesreleases large large amounts of amounts of energyenergy in in the the form of heatform of heat..

Water and PropertiesWater and Properties

• CohesionCohesion: attraction : attraction between substances of the between substances of the same kind. Ex: water same kind. Ex: water molecules are linked molecules are linked together in this process. This together in this process. This action forms action forms surface tensionsurface tension within water.within water.

• AdhesionAdhesion: Attraction : Attraction between different between different substances. – Allows for the substances. – Allows for the process of process of capillary actioncapillary action

• Question: What is the Question: What is the difference between cohesion difference between cohesion and adhesion?and adhesion?

CAPILLARY ACTIONCAPILLARY ACTION

Water and PolarityWater and Polarity

• There is an equal distribution There is an equal distribution of charge within the water of charge within the water molecule.molecule.

• Oxygen is Oxygen is electronegativeelectronegative – it – it desires electrons.desires electrons.

• There is a greater negative There is a greater negative charge on the oxygen than charge on the oxygen than the hydrogen.the hydrogen.

• Polar substances Polar substances will dissolve will dissolve other polar substances and other polar substances and some ionic compounds.some ionic compounds.

• Question: What does Question: What does electronegativity mean?electronegativity mean?

Review QuestionsReview QuestionsCornell Format 10.16.12Cornell Format 10.16.12

• 1. Define matter.• 2. Sketch an atom and identify its major parts.• 3. How is an element different from an atom?• 4. What part of the atom causes elements to

be different from one another?• 5. How does water regulate heat?• 6. Why does ice float?• 7. What is the difference between a polar

substance and a nonpolar substance?

Concentrations and SolutionsConcentrations and Solutions

• SoluteSolute: A substance which is : A substance which is being dissolved.being dissolved.

• SolventSolvent: Substance in which : Substance in which the solute is dissolved in.the solute is dissolved in.

• SolutionSolution = Solute + Solvent. = Solute + Solvent. Mixture in which one or Mixture in which one or more substances are more substances are uniformly distributed.uniformly distributed.

• ConcentrationConcentration: The amount : The amount of solute dissolved in a fixed of solute dissolved in a fixed amount of solutionamount of solution

• Water = universal solventWater = universal solvent

Acid and Bases• Water molecules can be

pulled apart.• H20 OH- and H30+• Hydroxide and Hydronium• If the number (concentration)

of Hydronium ions is greater than the number of Hydroxide ions in solution, then the solution is an acid.

• If the number of Hydroxide ions is greater = base

• H30+ > = acid, OH- > = base

Acid and Bases• The pH scale provides a

means for comparing relative concentrations of hydroxide and hydronium ions.

• The scale ranges from 0 to 14• A pH of 0 is very acidic and a

pH of 14 is very basic.• A pH of 7 is neutral. There is

an equal number of Hydroxide and Hydronium ions.

Acid and Bases• A change in of one unit of the

pH scale represents a 10-fold change in being acidic or basic.

• Ex. Lemon juice is 10x more acidic than orange juice.

• Ex. Orange juice is 1000x more acidic than urine.

Buffers• The control of pH is important in

living systems.• Certain metabolic reactions in

the body can only function within narrow pH ranges.

• BuffersBuffers: Chemical substances that neutralizes small amount of acids or bases when added to a solution.

• Buffering systems will maintain normal pH values within the body.

Chemical Reactions• In a chemical reaction one or more

substances change to produce one or more different substances.

• Two parts of the reaction are:1. Reactants2. Products

A + B C + D• Energy is required to move from

reactants to products.• This is called the energy of activation• Energy required to start the reaction.• Catalysts/Enzymes speed up the rate

of reaction by decreasing the activation energy.

Biology 10/18/2012Assignment

• Cornell Format• Vocabulary pg. 39• Pg. 46 # 2,6,9,11,12,14,16