Do Now #7A physical change occurs when a

substance changes form, but stays the same.

A chemical change occurs when a substance changes into a new, different substance.

1. In which Station Activities did you observe physical changes?

2. In which Station Activities did you observe chemical changes?

Physical vs. Chemical Physical Property

characteristics observed without changing the identity of the substance

Characteristics such as color, density, odor

Chemical Property

describes the ability of a substance to undergo changes in identity

Physical vs. Chemical

Lets think about the penny. What is the penny made out of?

Please tell me you didn’t say just copper!

Lets take a look at what the penny has done over the years.

Composition?

Why would the penny change (think of physical properties, as well as chemical properties?

B. Physical vs. Chemical Examples:

melting point

flammable

density

magnetic

tarnishes in

air

physical

chemical

physical

physical

chemical

Classify Each of the following as Physical or Chemical Properties

The boiling point of ethyl alcohol is 78°C.Physical property – describes inherent

characteristic of alcohol – boiling point

Diamond is very hard.Physical property – describes inherent

characteristic of diamond – hardness

Sugar ferments to form ethyl alcohol.Chemical property – describes behavior

of sugar – forming a new substance (ethyl alcohol)

Changes in MatterPhysical Changes are changes to matter

that do not result in a change of the fundamental components that make that substance (CHANGE IN CONDITION)State Changes – boiling, melting, condensing

Chemical Changes involve a change in the fundamental components of the substance (CHANGE IN MATERIAL)Produce a new substanceChemical reactionReactants Products

It’s a physical change if

It changes shape or size

It dissolves.

It changes phase (freezes, boils, evaporates, condenses)

•It’s a physical change if...

It’s a chemical change if….

It burns

Temperature changes without heating/cooling

It’s a chemical change if...

It bubbles (makes a gas)

It’s a chemical change if...

It changes color

It forms a precipitate

What kind of change is it if someone...

Tears up paper?

Physical change

Mixes salt and water?

Physical change

What kind of change is it if someone...

Burns paper?Chemical changeEvaporates salt water?Physical change

Table salt is stirred into water (left), forming a homogeneous mixture called a solution (right)

No chemical change occurs

when salt water is distilled

What kind of change is it if someone...

Mixes vinegar and baking soda?

Chemical change

Physical vs. Chemical

Examples:

rusting iron

dissolving in water

burning a log

melting ice

grinding spices

chemical

physical

chemical

physical

physical

Classify Each of the following as Physical or Chemical Changes

Iron is melted.Physical change – describes a state

change, but the material is still iron

Iron combines with oxygen to form rust.Chemical change – describes how iron

and oxygen react to make a new substance, rust

Sugar ferments to form ethyl alcohol.Chemical change – describes how sugar

forms a new substance (ethyl alcohol)

Properties of Matter

List of chemical changes possible.

Description by senses – shape, color, odor, etc.Measurable properties – density, boiling point, etc.

PROPERTIES

Old substance destroyed.New substance formed.

New form of old substance.No new substances formed.

CHANGE

CHEMICALPHYSICAL