Chapter 9 ReviewChapter 9 Review

SubstancesSubstances

A substance is either an element of a A substance is either an element of a compound.compound. An element is a kind of matter in which all An element is a kind of matter in which all

atoms are alike.atoms are alike.Examples – Hydrogen, Carbon, FluorideExamples – Hydrogen, Carbon, Fluoride

A compound is a material made of two or A compound is a material made of two or more elements that are combined.more elements that are combined.

Examples – HExamples – H22O, COO, CO22

An atom is a particle that makes up all matter.An atom is a particle that makes up all matter.

MixturesMixtures

A mixture is a material made up of two or more A mixture is a material made up of two or more substances.substances.

Mixtures do not always contain the same Mixtures do not always contain the same amounts of different substances.amounts of different substances. Heterogeneous mixture – a mixture in which different Heterogeneous mixture – a mixture in which different

materials can be easily distinguished materials can be easily distinguished Example – A solution with oil and waterExample – A solution with oil and water

Homogeneous mixture (solution) – a mixture in which Homogeneous mixture (solution) – a mixture in which two or more substances are uniformly spread out.two or more substances are uniformly spread out.

Example – A solution of salt and water.Example – A solution of salt and water.

Colloids and suspensionsColloids and suspensions

A colloid is a heterogeneous mixture that, A colloid is a heterogeneous mixture that, like a solution, never settles.like a solution, never settles. Examples – Gelatin, milkExamples – Gelatin, milk

A suspension is a heterogeneous mixture A suspension is a heterogeneous mixture containing a liquid in which visible particles containing a liquid in which visible particles settle.settle. Examples – Muddy waterExamples – Muddy water

Tyndall EffectTyndall Effect

The scattering of light by particles in a The scattering of light by particles in a mixture.mixture.

We can see the Tyndall effect in colloids.We can see the Tyndall effect in colloids.

SmogSmog

Smog is a form of air pollution.Smog is a form of air pollution.It is a colloid of small invisible pieces of solid It is a colloid of small invisible pieces of solid materials mixed with the gases that make up air.materials mixed with the gases that make up air.Some of the solid particles that make up smog Some of the solid particles that make up smog are dust.are dust.Unburned compounds in automobile exhaust Unburned compounds in automobile exhaust accounts for most of the particles in smog.accounts for most of the particles in smog.Warm air rises in the atmosphere.Warm air rises in the atmosphere. However, this warm air may be trapped beneath a However, this warm air may be trapped beneath a

layer of colder air. layer of colder air. The combination of the warm and cold air cause the The combination of the warm and cold air cause the

colloid smog.colloid smog.

Smog vs. FogSmog vs. Fog

Kind of Air PollutionKind of Air Pollution Cloud BankCloud Bank

Classic smog results from large Classic smog results from large amounts of coal burning in an area amounts of coal burning in an area caused by a mixture of smoke and caused by a mixture of smoke and

sulfur dioxidesulfur dioxide

Fog begins to form when water Fog begins to form when water vapor condenses into tiny liquid vapor condenses into tiny liquid

water droplets in the air. water droplets in the air.

It can inflame breathing passages, It can inflame breathing passages, decreasing the lungs' working decreasing the lungs' working

capacity, and causing shortness of capacity, and causing shortness of breath, pain when inhaling deeply, breath, pain when inhaling deeply,

wheezing, and coughing wheezing, and coughing

Fog reduces visibility and thus Fog reduces visibility and thus contributes to accidents, contributes to accidents, particularly with modes of particularly with modes of

transportation. transportation.

Physical propertiesPhysical properties

A physical property is any characteristic of a A physical property is any characteristic of a material that you can observe without changing material that you can observe without changing the substances that make up the material.the substances that make up the material.

Appearance and behaviorAppearance and behavior ShapeShape ColorColor SizeSize DensityDensity Melting pointMelting point Boiling pointBoiling point

Physical ChangePhysical Change

A change in size, shape or state of matter.A change in size, shape or state of matter.

When a substance freezes, boils When a substance freezes, boils evaporates, sublimes or condenses, it evaporates, sublimes or condenses, it undergoes physical change.undergoes physical change.

A color change indicates a physical A color change indicates a physical change.change.

Physical changes do not change the Physical changes do not change the identities of the substances in a material.identities of the substances in a material.

Chemical ChangeChemical Change

A change of one substance in a material to a A change of one substance in a material to a different substance.different substance.Examples include:Examples include: Fireworks explodingFireworks exploding Matches burningMatches burning Rotten eggsRotten eggs Burned toastBurned toast Rusty tires (exposed to oxygen)Rusty tires (exposed to oxygen) Odor is a clue that a chemical change has Odor is a clue that a chemical change has

occurred. occurred. Burning and rusting are chemical changes Burning and rusting are chemical changes

because new substances are produced.because new substances are produced.

Chemical PropertiesChemical Properties

A characteristic of a substance that A characteristic of a substance that indicates if it can undergo a certain indicates if it can undergo a certain chemical change.chemical change. Flammable or combustible substances.Flammable or combustible substances.

Law of Conservation of MassLaw of Conservation of Mass

Matter is neither created nor destroyed Matter is neither created nor destroyed during a chemical change.during a chemical change.

When we burn something, there is no loss When we burn something, there is no loss of mass.of mass. (Add the oxygen in the air with the log that (Add the oxygen in the air with the log that

burned)burned)