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AnnouncementsAnnouncements & Agenda& Agenda (01/17/07)(01/17/07)

Office Hours cancelled today (Red Wings)Office Hours cancelled today (Red Wings)CD quizzes due NOWCD quizzes due NOWQuiz 2 today!Quiz 2 today!See overhead for your clicker numberSee overhead for your clicker numberYou should currently be reading Ch 3 You should currently be reading Ch 3

Today:Today: Finish Heating/Cooling Curves (Ch 2)Finish Heating/Cooling Curves (Ch 2) Classification of Matter (3.1)Classification of Matter (3.1) Elements, Atoms, & Subatomic Particles (3.2-3.5)Elements, Atoms, & Subatomic Particles (3.2-3.5)

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Heat = mass x Heat = mass x TT x (Specific Heat) x (Specific Heat)

The amount of heat lost or gained by a substance isThe amount of heat lost or gained by a substance iscalculated from thecalculated from the

• mass of substance (g).mass of substance (g).• temperature change (temperature change (T).T).• specific heat of the substance (J/gspecific heat of the substance (J/g°C)°C)..

Last Time: Heat EnergyLast Time: Heat Energy

Key Point: If one substance “heats up” by a certain amount, another substance must exactly lose that same amount of heat!

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Last Time: Phases ChangesLast Time: Phases Changes

meltingmelting

vaporizationvaporizationcondensationcondensation

freezingfreezing

depositiondeposition

sublimationsublimation(e.g. freeze-drying)(e.g. freeze-drying)

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Last Time: Heat of Fusion/VaporizationLast Time: Heat of Fusion/Vaporization

Measure of heat energy released/absorbed Measure of heat energy released/absorbed during the appropriate phase change for 1 g of during the appropriate phase change for 1 g of substancesubstance

Water: Heat of fusion @ MP = Water: Heat of fusion @ MP = 80. cal 80. cal 1 g water1 g water

Water: Heat of vaporization @ BP = Water: Heat of vaporization @ BP = 540. cal 540. cal 1 g 1 g

waterwater

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Summary of Heating Processes: Summary of Heating Processes: Heating CurvesHeating Curves

A A heating curveheating curve • illustrates the illustrates the

changes of state as changes of state as a solid is heated.a solid is heated.

• uses sloped lines to uses sloped lines to show an increase in show an increase in temperature.temperature.

• uses plateaus (flat uses plateaus (flat lines) to indicate a lines) to indicate a change of state.change of state.

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Cooling CurveCooling Curve

Using the heating curve of water as a guide, Using the heating curve of water as a guide, draw a cooling curve for water beginning with draw a cooling curve for water beginning with steam at 110°C and ending at -20°C.steam at 110°C and ending at -20°C.

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To reduce a fever, an infant is packed in 250. g of ice. If To reduce a fever, an infant is packed in 250. g of ice. If the ice (at 0°C) melts and warms to body temperature the ice (at 0°C) melts and warms to body temperature (37.0°C), how many calories are removed from the body?(37.0°C), how many calories are removed from the body?Step 1: Diagram the changesStep 1: Diagram the changes

37°C 37°C T = 37.0°C - 0°C = 37.0°C T = 37.0°C - 0°C = 37.0°C

temperature increasetemperature increase

0°C 0°C solid liquidsolid liquid

meltingmelting

Combined Heat CalculationsCombined Heat Calculations

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Combined Heat Calculations Combined Heat Calculations (continued.)(continued.)

Step 2: Calculate the heat to melt ice (fusion)Step 2: Calculate the heat to melt ice (fusion) 250. g ice x 250. g ice x 80. cal80. cal = 2.000 = 2.000 10 1044 cal cal

1 g ice1 g ice

Step 3: Calculate the heat to warm the water fromStep 3: Calculate the heat to warm the water from 0°C to 37.0°C (SH of water = 1 cal/g)0°C to 37.0°C (SH of water = 1 cal/g)

250. g x 37.0°C x 250. g x 37.0°C x 1.00 cal1.00 cal = 9 250 cal = 9 250 cal g °C g °C

Total: Step 2 + Step 3Total: Step 2 + Step 3 = 29 200 cal = 29 200 cal(rounded to 3 SF)(rounded to 3 SF)

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29 Good Practice Problems (Ch 3)29 Good Practice Problems (Ch 3)

11 22 33 44 55

3.03, 3.05, 3.07, 3.11, 3.15, 3.17, 3.03, 3.05, 3.07, 3.11, 3.15, 3.17, 3.19, 3.23, 3.29, 3.35, 3.37, 3.41, 3.19, 3.23, 3.29, 3.35, 3.37, 3.41, 3.49, 3.51, 3.55, 3.59, 3.65, 3.67, 3.49, 3.51, 3.55, 3.59, 3.65, 3.67, 3.69, 3.73, 3.77, 3.79, 3.81, 3.85, 3.69, 3.73, 3.77, 3.79, 3.81, 3.85, 3.91, 3.95, 3.97, 3.101, 3.1033.91, 3.95, 3.97, 3.101, 3.103

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Chemistry: The Study of the Chemistry: The Study of the Properties & Behavior of MatterProperties & Behavior of Matter

Pure substance: matter with fixed/definite compositionPure substance: matter with fixed/definite compositionElementsElements: substance composed of only one type of atom: substance composed of only one type of atomCompoundsCompounds: combination of 2 or more elements in same : combination of 2 or more elements in same ratio (e.g. water, carbon dioxide, sodium chloride)ratio (e.g. water, carbon dioxide, sodium chloride)

Mixtures: two or more substances that can be Mixtures: two or more substances that can be separated by physical meansseparated by physical meansHeterogeneous mixturesHeterogeneous mixtures: non-uniform distribution of : non-uniform distribution of substances (e.g. mud = sand and saltwater, chocolate chip substances (e.g. mud = sand and saltwater, chocolate chip cookie)cookie)Homogenous mixturesHomogenous mixtures: uniform distribution of substances : uniform distribution of substances (e.g. saltwater = salt and water, air, Kool Aid)(e.g. saltwater = salt and water, air, Kool Aid)

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Visual SummaryVisual Summary

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ElementsElements

Pure substances that cannot be separated into Pure substances that cannot be separated into different substances by chemical processesdifferent substances by chemical processes

Are the building blocks of matter (the ABCs)Are the building blocks of matter (the ABCs)

112 elements known today112 elements known todayExamples: Examples: carboncarbon

goldgoldcalciumcalcium

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Symbols of ElementsSymbols of Elements

Use 1 or 2 letter abbreviations Use 1 or 2 letter abbreviations Capitalize the first letter onlyCapitalize the first letter only

Examples:Examples:

C carbon C carbon CoCo cobaltcobalt

N nitrogenN nitrogen CaCa calciumcalcium

F fluorine F fluorine Br bromine Br bromine O oxygen O oxygen Mg magnesiumMg magnesium

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Symbols from Latin NamesSymbols from Latin Names

ElementElement SymbolSymbol Latin nameLatin name

CopperCopper CuCu cuprumcuprum

GoldGold AuAu aurumaurum

LeadLead PbPb plumbumplumbum

MercuryMercury HgHg hydrargyrumhydrargyrum

PotassiumPotassium KK kaliumkalium

SilverSilver AgAg argentumargentum

SodiumSodium NaNa natriumnatrium

TinTin SnSn stannumstannum

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% Major Elements in the Body % Major Elements in the Body (Know These!)(Know These!)

OO 65.0 %65.0 % KK 0.34 0.34CC 18.018.0 SS 0.26 0.26HH 10.010.0 NaNa 0.14 0.14NN 3.0 3.0 ClCl 0.14 0.14CaCa 1.4 1.4 FeFe 0.004 0.004PP 1.0 1.0 ZnZn 0.003 0.003 MgMg 0.50 0.50

Trace ElementsTrace ElementsAs, Cr, Co, Cu, F, I, Mn, Mo, Ni, Se, Si, VAs, Cr, Co, Cu, F, I, Mn, Mo, Ni, Se, Si, V

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Atoms are building blocks of elements Atoms are building blocks of elements

Similar atoms in each elementSimilar atoms in each element

Different from atoms of other elementsDifferent from atoms of other elements

Two or more different atoms bond in simple Two or more different atoms bond in simple

ratios to form compoundsratios to form compounds

Dalton’s Atomic TheoryDalton’s Atomic Theory

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Conservation LawsConservation Laws1.1. AtomsAtoms are conserved during physical are conserved during physical

and chemical transformationsand chemical transformations– – atoms are neither created nor destroyed atoms are neither created nor destroyed

during a chemical or physical processduring a chemical or physical process

2.2. Mass Mass is conserved during physical and is conserved during physical and chemical transformationschemical transformations– – mass is neither created nor destroyed mass is neither created nor destroyed during a chemical or physical processduring a chemical or physical process

3.3. ChargeCharge is also conserved during is also conserved during physical and chemical transformationsphysical and chemical transformations

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Methane (CH4) reacts with oxygen (O2) to produce carbon dioxide (CO2) and water (H2O). COUNT THE ATOMS!

SEE BOB DEMO!

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Subatomic ParticlesSubatomic Particles

Atoms contains subatomic particles,Atoms contains subatomic particles,

• protons protons have a positive (+) charge.have a positive (+) charge.• electrons electrons have a negative (-) charge.have a negative (-) charge.• like charges like charges repelrepel and unlike charges and unlike charges

attractattract..• neutronsneutrons are neutral. are neutral.

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Structure of the AtomStructure of the Atom

• dense nucleus that dense nucleus that contains protons and contains protons and neutrons.neutrons.

• of electrons in a of electrons in a large empty space large empty space around the nucleus.around the nucleus.

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Atomic Mass ScaleAtomic Mass Scale

On the atomic mass scale for subatomic particles,On the atomic mass scale for subatomic particles,

• 1 atomic mass unit (amu) has a mass equal to 1/12 of 1 atomic mass unit (amu) has a mass equal to 1/12 of the mass of the carbon-12 atom.the mass of the carbon-12 atom.

• a proton has a mass of about 1 (1.007) amu.a proton has a mass of about 1 (1.007) amu.

• a neutron has a mass of about 1 (1.008) amu.a neutron has a mass of about 1 (1.008) amu.

• an electron has a very small mass, 0.000549 amu.an electron has a very small mass, 0.000549 amu.

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SummarySummary

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Atomic Number = The Identity of Atomic Number = The Identity of the Elementthe Element

Counts the number Counts the number

of of

protonsprotons

in an atomin an atom

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All Atoms of the Same Element All Atoms of the Same Element Have the Same # of Protons!!!Have the Same # of Protons!!!

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NaNa

11 protons

Symbol

2525www.webelements.com

2626

Mass NumberMass Number

Since protons and neutrons account for most Since protons and neutrons account for most of the mass of the atom, of the mass of the atom,

count the number count the number

of of

protons and neutronsprotons and neutrons

to determine the mass number!!!to determine the mass number!!!

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• represents a particular atom of an element.represents a particular atom of an element.

• gives the mass number in the upper left corner gives the mass number in the upper left corner and the atomic number in the lower left corner.and the atomic number in the lower left corner.

ExampleExample: An atom of sodium with atomic : An atom of sodium with atomic number 11 and a mass number 23 has the number 11 and a mass number 23 has the following atomic symbol:following atomic symbol:

mass number mass number 23 23 NaNa

atomic numberatomic number 1111

Nuclear SymbolNuclear Symbol

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An atom of An atom of • an element is electrically neutral; the net charge of an element is electrically neutral; the net charge of

an atom is zero.an atom is zero.• has an equal number of protons and electrons. has an equal number of protons and electrons.

number of protons = number of electronsnumber of protons = number of electrons

Aluminum has 13 protons and 13 electrons. The net Aluminum has 13 protons and 13 electrons. The net charge is zero. charge is zero.

13 protons (13+) + 13 electrons (13 -) = 013 protons (13+) + 13 electrons (13 -) = 0

Electrons in An AtomElectrons in An Atom