Matter and Change I. Chemistry As a Physical Science.

Matter and Change

I. Chemistry As a Physical Science

Chemistry

Chemistry the study of the composition, structure,

and properties of matter and the changes that matter undergoes

Chemical any substance that has a definite

composition or is used or produced in a chemical process

6 Branches of Chemistry

organic chemistry- the study of most carbon-containing chemicals

inorganic chemistry- the study of nonorganic substances

6 Branches of Chemistry

biochemistry- the study of substances and processes occurring in living things

analytical chemistry- the identification of the components and composition of materials

6 Branches of Chemistry

physical chemistry- the study of the properties and changes of matter and their relation to energy

6 Branches of Chemistry

Theoretical chemistry- the use of mathematics and computers to understand the principles behind observed chemical behavior and to design and predict new compounds

Chemistry vs. Technology

Basic research- the pursuit of chemical knowledge for its own sake

Applied research- research that is directed toward a practical goal or application

Chemistry vs. Technology

Basic research can lead directly to an application, but an application can’t exist before research is done to explain how it works.

→ need a problem first

Chemistry vs. Technology

Chemistry differs from technology… i.e. AspirinDetermining the structure of aspirin

is chemistryUsing aspirin to relieve pain and

reduce fever is technology

Ch. 1 – Matter and Change

II. Matter and Its Properties

Matter Flowchart

MATTER

Can it be physically separated?

Homogeneous Mixture

(solution)

Heterogeneous Mixture Compound Element

MIXTURE PURE SUBSTANCE

yes no

Can it be chemically decomposed?

noyesIs the composition uniform?

noyes

Colloids Suspensions

Pure Substances

Every sample has exactly the same characteristic properties

Every sample has exactly the same composition

Pure Substances

Element composed of identical atoms EX: copper wire, aluminum foil

Pure Substances

Compound

composed of 2 or more elements in a fixed ratio

properties differ from those of individual elements

EX: table salt (NaCl)

Pure Substances

For example…

Two different compounds, each has a definite composition.

Matter Flowchart

Examples:

graphite

pepper

sugar (sucrose)

paint

soda

element

hetero. mixture

compound

hetero. mixture

solution

Mixtures

Variable combination of 2 or more pure substances.

Heterogeneous Homogeneous

Mixtures

Solution homogeneous very small particles particles don’t settle EX: rubbing alcohol

Mixtures

Suspension heterogeneous large particles particles settle EX: fresh-squeezed

lemonade

Mixtures

Examples:

mayonnaise

muddy water

fog

saltwater

Italian salad dressing

colloid

suspension

colloid

solution

suspension

C. Johannesson

Extensive vs. Intensive

Extensive Property

depends on the amount of matter present

Intensive Property

depends on the identity of substance, not the amount

C. Johannesson

Extensive vs. Intensive

Examples:

boiling point

volume

mass

density

conductivity

intensive

extensive

extensive

intensive

intensive

C. Johannesson

Physical vs. Chemical

Physical Property

can be observed without changing the identity of the substance

Chemical Property

describes the ability of a substance to undergo changes in identity

C. Johannesson

Physical vs. Chemical

Examples:

melting point

flammable

density

magnetic

tarnishes in air

physical

chemical

physical

physical

chemical

C. Johannesson

Physical vs. Chemical

Physical Change

changes the form of a substance without changing its identity

properties remain the same

Chemical Change

changes the identity of a substance

products have different properties

C. Johannesson

Physical vs. Chemical

Signs of a Chemical Change

change in color or odor

formation of a gas

formation of a precipitate (solid)

change in light or heat

C. Johannesson

Physical vs. Chemical

Examples:

rusting iron

dissolving in water

burning a log

melting ice

grinding spices

chemical

physical

chemical

physical

physical

C. Johannesson

Four States of Matter

Solids particles vibrate but can’t

move around fixed shape fixed volume

C. Johannesson

Four States of Matter

Liquids particles can move

around but are still close together

variable shape fixed volume

C. Johannesson

Four States of Matter

Gases particles can separate and

move throughout container variable shape variable volume

C. Johannesson

Four States of Matter

Plasma particles collide with enough energy

to break into charged particles (+/-) gas-like, variable

shape & volume stars, fluorescent

light bulbs, CRTs

Ch. 1 – Matter and Change

III. Elements

33

Modern Periodic TablePeriod- horizontzal row

34

Group or Family - Vertical column

Modern Periodic Table

Metals, Nonmetals, Metalloids

Metals

solids at room temperature, have a grayish color and shiny surface and conduct electricity

largest region excellent conductor of heat lustrous ductile malleable

Nonmetals

second largest region on table vary in properties a bit poor conductor gases or brittle solids at room temp.

Metalloids

an element having properties of metals as well as nonmetals

some have conductive properties some have luster some brittle solid at room temp. semiconductors