Create foldable

with three flaps on one

side and four on the

other.

Physical and Chemical Changes

Review

• Matter: anything that has mass and takes up space

• Energy: ability to do work or cause change–Energy is used anytime a change in

matter occurs

Kinds of Matter• The fundamental

kinds of matter interact to form everything around us. They are:– elements– compounds– mixtures

Elements• Elements are substances that

cannot be broken down into other substances chemically or physically

• Examples:– sodium– oxygen– carbon– aluminum

Compounds• Compounds are substances

made of two or more elements combined chemically

Compounds have properties different from those of the

original elements

• Examples:– Water: hydrogen and oxygen– Table salt: sodium and

chlorine

Mixtures• Mixtures are a

combination of two or more substances that are not chemically combined. They can be separated again.

• examples– salad– frosted cake– kool-aid

Properties of Matter

• Property: characteristic• There are two kinds of properties for matter:

– Physical properties– Chemical properties

physical and chemical properties are used to identify, describe, and classify matter

Physical Properties• Observe physical looks of

something• Also observed without changing

the substance into something else• Examples:

– Color– Density– Shape– Boiling Point– Mass

• Can you name others?

Chemical Properties• Observed only when substance is

changed and interacts with another substance

• Examples:– flammability: able to burn (reacts

with oxygen)– rusting: combining with oxygen

to form rust– Explosive: ability to explode

(reacts with oxygen)– Corrosive: ability to corrode or

wear down other substances• can you think of others?

Physical and Chemical Properties Review

• What is an example of a physical property of a candle?

• What is an example of a chemical property of a candle?

During a“physical change”

a substance changes some physical property…

During a“physical change”

a substance changes some physical property…

H2O

…but it is still the same material with the same chemical composition.

…but it is still the same material with the same chemical composition.

H2Ogas

solid

liquid

Physical and Chemical PropertiesExamples of Physical Properties

Boiling point Color Slipperiness Electrical conductivity

Melting point Taste Odor Dissolves in water

Shininess (luster) Softness Ductility Viscosity (resistance to flow)

Volatility Hardness Malleability Density (mass / volume ratio)

Examples of Chemical Properties

Burns in air Reacts with certain acids Decomposes when heated

Explodes Reacts with certain metals Reacts with certain nonmetals

Tarnishes Reacts with water Is toxic

Ralph A. Burns, Fundamentals of Chemistry 1999, page 23Chemical properties can ONLY be observed during a chemical reaction!

Changes in Matter

• There are two kinds of changes in matter: – Physical changes– Chemical changes

Energy is used anytime a change in matter occurs, whether it is physical or

chemical.

Physical Changes• Alters form or appearance of

material, but does not change material into brand new substance

• Examples: – chopping wood– bending wire– molding clay

• phase changes are physical changes– Melting– Freezing– Boiling– Condensing

Chemical Changes• A chemical reaction

that produces new substances’

• It rearranges the atoms

• Examples:– wood burning– sour milk

5 signs of a Chemical Reaction

1. Color Change 2. Energy Change 3. Precipitate Formed4. Gas Production 5. Property Change

Energy

• ENERGY IS USED ANYTIME A CHANGE IN MATTER OCCURS

• Energy has many forms: – Thermal– motion– electromagnetic– electrical– chemical

Chemical Change:Chemical Change:

Any change involving a rearrangement of atoms.Any change involving a

rearrangement of atoms.

Chemical Reaction:Chemical Reaction:

The process of a chemical change...The process of a

chemical change...

During a“chemical reaction”new materials are

formed by a change in the way atoms are bonded together.

During a“chemical reaction”new materials are

formed by a change in the way atoms are bonded together.

The formation of a mixture

The formation of a mixture

The formation of a compound

The formation of a compoundChemical Change

Chemical Change

Physical Change

Physical Change

Physical & Chemical Changes

Limestone,CaCO3

crushing

PHYSICALCHANGE

Crushed limestone,CaCO3

heating

CHEMICALCHANGE

PyrexPyrex

CO2

CaO

Lime andcarbon dioxide,

CaO + CO2

PyrexPyrex

O2

H2O

PyrexPyrex

H2O2

Light hastens the decomposition of hydrogen peroxide, H2O2. The dark bottle in which hydrogen peroxide is usually storedkeeps out the light, thus protecting the H2O2 from decomposition.

Sunlight energy