Introduction & Matter & ChangeAn Overview of Modern Chemistry

Chapters 1& 2

Chemistry is…• The study of the composition (not compost!),

structure, and properties of matter and the changes it undergoes

• Answers ?s-What is that material made of?• What is its makeup & internal arrangement• How does it behave when heated? Cooled?• Why does this material behave as it does?

Instruments refine our ability to measure- sight, weight, length

6 Branches of Chemistry1. Organic Chemistry- the study of carbon

containing compounds

2. Inorganic Chemistry- the study of all substances not classified as organic, compounds without carbon- ex. Br

3. Physical Chemistry- the study of the properties and changes of matter and their relation to energy

4. Analytical Chemistry- The identification of the components and composition of materials

5. Biochemistry- The study of substances and processes occurring in living things

6. Theoretical Chemistry- The use of math and computers to understand and predict chemical behaviors

Types of Research

Basic ResearchRoy Plunkett- discovering Teflon

Applied ResearchReducing ozone brings about new refrigerants

Technological Development

1960 Business Computer

Historical Perspective of ChemistryAristotle- made observations of the natural world

Believed that the world was made of what 4 elements?

“Earth, Wind & Fire” & water

Alchemy- The attempt to turn metals into gold for wealth dominated “science” for 1,500 yrs.

Charles Lavoisier- observed & tested the natural world; the “Father of Chemistry”

The Scientific Method

Manipulated /Independent variable- The variable that is changed during an experiment;

Responding /Dependent variable- The variable that is observed during an experiment

Matter & It’s Properties

• Mass- is a measure of the amount of matter• Matter-anything that has mass & takes up

space• Is air matter? Name things that aren’t matter.

Yes!

Matter make-up

• Atom- smallest unit of an element that maintains the properties of that element

• Element- a pure substance made of only one kind of atom

• Compound- substance that is made from the atoms of 2 or more elements chemically bonded.

Matter!One atom

elemental gold (Au)

Compound -computer generated

Does this relate??

Properties of amount

Extensive Properties• Depend on the amount of

matter that is present• Ex. Volume– Mass– Amount of energy in a

substance

Intensive Properties• Properties that do not

depend on the amount of matter present

• Ex. Melting point– Boiling point– Density– Ability to conduct

electricity– Ability to conduct heat

Physical Characteristics

Properties• Physical Property:

characteristic that can be observed or measured without changing the identity of the substance

• Ex. Melting point, boiling point, color, weight, odor

Changes• Physical Change:• A change in a substance

that does not involve a change in the identity of the substance

• Ex. Grinding, cutting, melting, and boiling a material, change of state

Changes of State

Red Cube- solid (art in NYC)Solid Matter: State that has definite volume and definite shape

Diet Coke- liquidLiquid Matter: State that has definite volume and indefinite shape

Changes of State

Plasma is found in a fluorescent bulbPlasma Matter: high temperature physical state of matter in which atoms lose their electrons

Smoke bomb!Gas Matter: physical state that does not have definite volume or definite shape

Some changes to a substance change it’s identity-

Chemical Characteristics

Properties• Chemical Property-relates

to a substance’s ability to undergo changes that transform it into different substances

• Ex. Charcoal (Carbon) to burn to become CO2;

• Iron (Fe) to rust with O2

• Silver (Ag) to tarnish with• Sulfur (S) present

Changes• Chemical Change- A change in

which one or more substances are converted into different substances

• Ex. C + O2 -> CO2

• Reactant+Reactant ->Product

Means “yield” Decomposition is the

breakdown of a substanceHg(II)O2 Hg+2 + O2

Chemical Reactions

Composition

3 CO2 + 3 H2O C3H6O 3+ 3 O2

Making glucose

Decomposition

Hg(II) O Hg+2 + O2

Distinguish between Physical vsChemical Characteristics-

Distinguish between Physical & Chemical Changes

Energy in relation to matter• Chemical changes often require the

absorption of heat energy and release of energy

• Think of a fire in the fireplace• Chemical changes often release light energy• Think of burning a candle• Energy can be absorbed or released but is not

destroyed.• Think of the law of conservation of energy

Classification of Matter

• Matter• Mixture Pure Substance(blend of 2 or more kinds (fixed composition with Matter retaining its own same characteristics & Identity & properties) composition; same ratio)

• Homogeneous Compounds• Air, sugar dissolved in water water, NaCl (salt)

• Heterogeneous Elements• Granite, wood, blood gold (Au), Silver (Ag)

Mixture vs. Pure Substances

1. Air?2. Purified

water?3. Handful of

pennies & dimes?

4. Copper wire?5. Oil and

vinegar salad dressing?

6. Gold ore?

Gas, mixture , homogeneous

Liquid, pure substance, compound, homogeneous

Solid, mixture, heterogeneous

Solid, pure substance, element

Liquid, mixture, heterogeneous

Solid, mixture, heterogeneous

Hetero or Homo?

Some mixtures are uniform in composition (while retaining its own identity and properties). These homogeneous mixtures are also called solutions. Example: saltwater

Heterogeneous mixtures are not uniform throughout- mixture of clay and water

The Organization of Elements- The Periodic Table

Periods-------------------------------------------------

GroupsOr

Families^|||||||||

Elements

An element is a pure substance made of only one kind of atom.

Some elements were named in Latin. Below are some:Cu cuprumAu aurumFe ferrumPb plumbum

Can you give the English name for them?

What about Sb?Na?K?Ag?

80

Hg200.59

Main Element Groups

• Metals• An element that is a good

conductor of heat and electricity.

• Characteristics:• Solid at room temp.• Malleability• Ductile• Tensile Strength• Most are silvery/grayish

luster

• Non metals• An element that is a

poor conductor of heat and electricity

• Characteristics:• Often gas at room temp• Ex. N, O, F, Cl• Solids tend to be brittle• Not malleable • Fewer in number

2 Exceptional Elemental GroupsMetalloids: An element that has some characteristics of metals and some characteristics of nonmetals.Metalloids make excellent semi-conductors found in computers, calculators, digital watches, televisions & radios

Noble Gases: Found as recently as 1962. Low reactivity characterize this group. Also known as Inert Gases. Name them:What can you assume about He from observing it’s use in balloons?

He, Ne, Ar, Kr, Xe, Rn, Uuo; He gas must be lighter than air