Welcome to the Welcome to the World of World of ChemistryChemistry

Pre-AP and Regular: Ch. 1-2

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It’s because he was a teacher!!!

The Language of The Language of ChemistryChemistryThe Language of The Language of ChemistryChemistry

• CHEMICAL ELEMENTSCHEMICAL ELEMENTS - - – pure substances that cannot be decomposed by pure substances that cannot be decomposed by

ordinary means to other substances.ordinary means to other substances.

SodiumBromine

Aluminum

The Language of The Language of ChemistryChemistryThe Language of The Language of ChemistryChemistry

• The elements, The elements, their names, and their names, and symbols are given symbols are given on theon the PERIODIC PERIODIC TABLETABLE

• How many How many elements are elements are there?there?

The Periodic TableThe Periodic Table

Dmitri Mendeleev (1834 - 1907)Dmitri Mendeleev (1834 - 1907)

Glenn Glenn SeaborgSeaborg

(1912-1999)(1912-1999)• Discovered 8 Discovered 8

new elements.new elements.

• Only living Only living person for person for whom an whom an element was element was named.named.

Branches of Chemistry

• Many major areas of study for Many major areas of study for specializationspecialization

• Several career opportunitiesSeveral career opportunities

• Also used in many other jobsAlso used in many other jobs

1. Organic Chemistry

• Organic is the study of Organic is the study of matter that contains carbonmatter that contains carbon

• Organic chemists study the Organic chemists study the structure, function, structure, function, synthesis, and identity of synthesis, and identity of carbon compoundscarbon compounds

• Useful in petroleum Useful in petroleum industry, pharmaceuticals, industry, pharmaceuticals, polymerspolymers

2. Inorganic Chemistry

• Inorganic is the Inorganic is the study of matter that study of matter that does NOT contain does NOT contain carboncarbon

• Inorganic chemists Inorganic chemists study the structure, study the structure, function, synthesis, function, synthesis, and identity of non-and identity of non-carbon compoundscarbon compounds

• Polymers, Polymers, MetallurgyMetallurgy

3. Biochemistry

• Biochemistry is Biochemistry is the study of the study of chemistry in chemistry in living thingsliving things

• Cross between Cross between biology and biology and chemistrychemistry

• Pharmaceuticals Pharmaceuticals and geneticsand genetics

4. Physical Chemistry

• Physical Physical chemistry is the chemistry is the physics of physics of chemistry… the chemistry… the forces of matterforces of matter

• Much of IPC is Much of IPC is computationalcomputational

• Develop Develop theoretical ideas theoretical ideas for new for new compoundscompounds

5. Analytical Chemistry

• Analytical Analytical chemistry is the chemistry is the study of high study of high precision precision measurementmeasurement

• Find composition Find composition and identity of and identity of chemicalschemicals

• Forensics, quality Forensics, quality control, medical control, medical teststests

Is This Your Version of the Scientific Method??

Or Do You Feel Like This When Doing Science?

Scientific Method

1. State the problem clearly.2. Gather information.3. Form a hypothesis.4. Test the hypothesis.5. Evaluate the data to form a conclusion.

If the conclusion is valid, then it becomes a theory. If the theory is found to be true over along period of time (usually 20+ years) with no counter examples, it may be considered a law.

6. Share the results.

Nature of Science Terms

• Fact: an observation that has been repeatedly confirmed and for all practical purposes is accepted as “true”.

• Hypothesis: A tentative statement about the natural world leading to deductions that can be tested. If the deductions are verified, the hypothesis is corroborated. If false, the hypothesis must be abandoned or revised.

• Law: A descriptive generalization about how some aspect of the natural world behaves under stated circumstances.

• Theory: A well-substantiated explanation of some aspect of the natural world that can incorporate facts, laws, inferences, and tested hypothesis.

Graphs

Bar Graph

shows how many of something

are in each category

0

2

4

6

8

10

A B C D F

Chemistry Grades

Pie Graph shows how a whole is broken into parts

40%

25%20%

15%Entertainment (40%)

Food (25%)

Clothing (20%)

Savings (15%)

Percentage ofWeekly Income

Line Graphshows continuous change

0

10

20

30

40

50

60

Jan Feb Mar Apr

Month

Sh

are

Pri

ce (

$)

Stock Price over Time

Elements of a “good” line graph

• axes labeled, with units

• use the available space

• title

• neat

Temp. v. Vol. for a Gas at Constant Pressure

0123456789

10

120 140 160 180 200 220 240

Temp. (K)

Vo

lum

e (

L)

Graphs

• Line Graph– Used to show trends or continuous change

• Bar Graph– Used to display information collected by counting

• Pie Graph– Used to show how some fixed quantity is broken down into parts

0

20

40

60

80

1s t

Qtr

2nd

Qtr

3r d

Qtr

4th

Qtr

Line Graph

Mass (g)

Age (Year of Penny)

Mass (g)

Age (Year of Penny)

Mass (g)

Age (Year of Penny)

Mass (g)

Age (Year of Penny)

How does the mass of a penny change with age?

A B

C D

Bar Graph

0

10

20

30

40

50

60

70

1st Qtr 2nd Qtr 3rd Qtr 4th Qtr

ABCDN

um

ber

of

Stu

den

ts

Chemistry Grades

Descriptive title

Legend

Axis labeled (with units)

Pie Graph

Pie Graphs

Earth's Crust

Oxygen49%

Silicon26%

Other9%

Aluminum8%

Iron5%

Calcium3%

OxygenSiliconOtherAluminumIronCalcium

Matter And Matter And EnergyEnergy

Chemistry: Chapter 2

The Nature of MatterThe Nature of MatterThe Nature of MatterThe Nature of Matter

Chemists are interested in the nature of matter Chemists are interested in the nature of matter and how this is related to its atoms and and how this is related to its atoms and molecules.molecules.

GoldGold MercuryMercury

Chemistry & Chemistry & MatterMatter

• We can explore the We can explore the MACROSCOPIC MACROSCOPIC world — what we world — what we can see — can see —

• to understand the to understand the PARTICULATEPARTICULATE worlds we cannot see.worlds we cannot see.

• We write We write SYMBOLSSYMBOLS to describe to describe these worlds.these worlds.

A Chemist’s View of A Chemist’s View of WaterWater

H2O (gas, liquid, solid)

MacroscopicMacroscopicMacroscopicMacroscopic

SymbolicSymbolicSymbolicSymbolicParticulateParticulateParticulateParticulate

A Chemist’s ViewA Chemist’s View

2 H2(g) + O2 (g) --> 2 H2O(g)

MacroscopicMacroscopicMacroscopicMacroscopic

SymbolicSymbolicSymbolicSymbolicParticulateParticulateParticulateParticulate

Kinetic Nature of Kinetic Nature of MatterMatter

Kinetic Nature of Kinetic Nature of MatterMatter

Matter consists of atoms Matter consists of atoms and molecules in motion.and molecules in motion.

STATES OF MATTERSTATES OF MATTERSTATES OF MATTERSTATES OF MATTER•SOLIDSSOLIDS — — have rigid shape, fixed have rigid shape, fixed

volume. External shape can reflect the volume. External shape can reflect the atomic and molecular arrangement.atomic and molecular arrangement.

–Reasonably well understood.Reasonably well understood.

•LIQUIDSLIQUIDS — — have no fixed shape and have no fixed shape and may not fill a container completely. may not fill a container completely.

–Not well understood.Not well understood.

•GASESGASES — — expand to fill their container. expand to fill their container.

–Good theoretical understanding.Good theoretical understanding.

OTHER STATES OF OTHER STATES OF MATTERMATTER

OTHER STATES OF OTHER STATES OF MATTERMATTER

•PLASMAPLASMA — — an electrically charged an electrically charged gas; Example: the sun or any other stargas; Example: the sun or any other star

•BOSE-EINSTEIN BOSE-EINSTEIN CONDENSATECONDENSATE — — a condensate that a condensate that forms near absolute zero that has forms near absolute zero that has superconductive properties; Example: superconductive properties; Example: supercooled Rb gassupercooled Rb gas

Physical Physical PropertiesProperties

What are some physical What are some physical properties?properties?

• colorcolor

• melting and boiling melting and boiling pointpoint

• odorodor

GraphiteGraphite — — layer structure layer structure of carbon of carbon atoms reflects atoms reflects physical physical properties.properties.

Physical ChangesPhysical Changes– can be observed without

changing the identity of the substance

SomeSome physical changes physical changes would bewould be

• boiling of a liquidboiling of a liquid• melting of a solidmelting of a solid• dissolving a solid in a dissolving a solid in a

liquid to give a liquid to give a homogeneous mixturehomogeneous mixture — — a SOLUTION.a SOLUTION.

Chemical Properties and Chemical Properties and Chemical ChangeChemical Change

• Chemical change Chemical change or or chemical reactionchemical reaction — — transformation of one or transformation of one or more atoms or molecules more atoms or molecules into one or more different into one or more different molecules.molecules.

•Burning hydrogen (HBurning hydrogen (H22) in ) in oxygen (Ooxygen (O22) gives H) gives H22O.O.

Sure Signs of a Sure Signs of a Chemical ChangeChemical Change

• HeatHeat

• LightLight

• Gas Produced Gas Produced (not from (not from boiling!)boiling!)

• Precipitate – a Precipitate – a solid formed by solid formed by mixing two mixing two liquids togetherliquids together

http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA0/MOVIES/S1047.MOV

Physical vs. Chemical

• Examples:

– melting point

– flammable

– density

– magnetic

– tarnishes in air

physical

chemical

physical

physical

chemical

Physical vs. Chemical

• Examples:

– rusting iron

– dissolving in water

– burning a log

– melting ice

– grinding spices

chemical

physical

chemical

physical

physical

Matter Flowchart

MATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

Colloids Suspensions

Element

Types of Mixtures

• Variable combination of 2 or more pure substances.

Heterogeneous –visibly separate phases

Homogeneous – Same throughout

There is no observable change in the quantity of matter during a chemical reaction or a physical change.

In other words, matter cannot be created nor destroyed. It is just converted from one form to another

Now You Should Be Able To…

Differentiate between physical and chemicalproperties of matter.

Physical property – anything that you can measureor observe without changing the identity ofthe substance: density, viscosity, fluidity, volume, mass, color, state,conductivity, melting point, boiling point,odor, solubility

Chemical property – relates to the substances abilityto undergo changes that transform it intodifferent substances: reactivity, oxidizers, (haven’t learned this yet)reducers, reacts with acids, flammability,corrosiveness, stability, reacts with water

• Investigate and identify properties of mixtures andpure substances. (solutions, colloids, suspensions,compounds, and elements)

• Mixtures – blend of two or more substances withvariable composition including bothhomogeneous and heterogeneous mixtures

• Pure substances – elements or compounds; havefixed composition and properties

• Use properties of samples to determine mixture orpure substances using examples likesandwich, rocks, sand, copper, water

• Investigate 9 different kinds of mixtures includingsolid in liquid, liquid in liquid, gas in liquid, etc.

And Know This…

One More Thing…

Analyze examples of solids, liquids, and gases todetermine their compressibility, structure, motion ofparticles, shape, and volume.

Property solid liquid gascompressibility no very little yesstructure ordered intermediate noneshape definite indefinite indefinitevolume definite definite indefiniteMotion vibrate flow rapid

random