Chemistry as the

“Central Science” Chemistry = the study of matter and the transformation

it undergoes

EVERYTHING is a CHEMICAL

Table salt = sodium chloride, NaCl

Table sugar = sucrose, C12H22O11

Clothes: Wool? Cotton? Polyester?

Body: lipids, Proteins, Carbohydrates, DNA/RNA

You name it– it’s a chemical!

Chemistry as the

“Central Science” Chemistry is the driving force behind many “liberal

arts”

Composition of paints? Colors?

Economies of industrial nations

#1 commercial chemical is sulfuric acid– LOTS of uses!

All idustry involves chemical processes

Economies of Developing Nations

Agriculture depends on chemicals as fertilizers, pesticides

Politics and Natural Resources

The Study of Chemistry

Chemistry is everywhere!

Matter is everywhere!

Thus, chemistry matters!

Chemistry involves the

study of matter – its

properties and behavior.

Matter Matter is anything that: a) has mass, and

b) takes up space

Mass = a measure of the amount of

“stuff” (or material) the object contains

(don’t confuse this with weight, a

measure of gravity)

Volume = a measure of the space

occupied by the object

Property Description Example

Hardness Ability of 1 substance

to scratch another

Diamond can scratch

glass

Viscosity Resistance to

flowing

Solubility Ability to dissolve

in water

NaCl dissolves

easily in water so

it’s soluble

•A physical change occurs when the substance

changes state but does not change its chemical

composition.

•For example: water freezing into ice, cutting a piece

of wood into smaller pieces, etc.

•The form or appearance has changed, but the

properties of that substance are the same (i.e. it has

the same melting point, boiling point, chemical

composition, etc.)

After a PHYSICAL CHANGE,

the appearance of the substance may be

different but it is still the same substance

EXAMPLES:

Cutting a steak

Cracking an egg

Chopping

wood

Bending a

metal

Tearing paper

Chemical Properties determine how a

substance interacts with other

substances

Some examples are:

*flammability

*reactivity to an acid

*reactivity to water

•A chemical change occurs when a substance changes into

something new.

•This occurs due to heating, chemical reaction, etc.

•You can tell a chemical change has occurred if the density,

melting point or freezing point of the original substance

changes. Many common signs of a chemical change can be

seen (bubbles forming, mass changed, etc).

Here are some signs that a

CHEMICAL CHANGE took place:

New color

New odor or smell

Gas bubbles or smoke

An increase or decrease in

temperature

You can’t go

back to the

original

substances

after a

chemical

change

(reaction) has

occurred!!

Baking

soda

reacting

w/

vinegar

Burning

wood

Physical or Chemical Change???

A. You cut a sheet

of aluminum foil

in half

B. Your friend

melts some butter

for her popcorn

C. Your Mom

lights a candle in a

dark room

D. Rubbing alcohol

evaporates from your

hand

E. Hydrogen peroxide

bubbles when you put

it on a cut on your leg

F. You leave the milk

on the counter all

night and discover it

has soured in the

morning

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