Classifying Matter - PBworksscience3000.pbworks.com/w/file/fetch/86303467/Chemistry 2... · Classifying Matter. Mixture: A combination of pure substances (elements/compounds) that

Classifying Matter

Matter

Pure Substance:

Substance made up

of only one kind of

matter (particle).

Element:

Contains only one kind of atom.

The chemical symbol

has one capital letter.

Compound:

A pure substance that is made

of 2 or more different

elements that are combined

together chemically.

The chemical symbol has

2 or more capital letter.

Ex: NaClEx: Na

Example of an Element: Oxygen (O)

Oxygen

Example of an Element: Hydrogen (H)

Hydrogen

Example of a compound?

• Here you have a mixture of hydrogen and oxygen. They are

not chemically combined (joined) to each other though. Not

a compound.

HydrogenHydrogen

HydrogenHydrogen

Oxygen

Oxygen

Oxygen

Example of a compound?

• Water: H2O. Why is this a compound but not what was on the previous slide?

Hydrogen Hydrogen

Oxygen

“Chemically

combined”

• Because the elements on the previous slide were not chemically combined.

Water is now a new substance. It

is has different properties than

oxygen and hydrogen.

Classifying Matter

Mixture:

A combination of pure substances

(elements/compounds) that are NOT

chemically combined

(more than one type of particle).

Homogeneous (Homo = same):

The different substances

that make up the mixture

are not individually visible.

Also called a Solution.

Heterogeneous

(Hetero = different):

The different substances

that make up the mixture

are visible. Also called

mechanical mixture.

“Dissolving” Sugar in coffee is an

example of a solution because:

1) You cannot tell the sugar apart from the coffee (HOMOgeneous).

2) It is a mixture of two substances that are not chemically combined (coffee remains coffee and sugar remains sugar).

Classifying Matter

A salad is an example of a Mechanical

heterogeneous mixture because:

1) All the different substances that make up the salad are visible (HETEROgeneous).

2) It is a mixture of two or more substances that are not chemically combined (Lettuce remains lettuce, tomato remains tomato).

Heterogeneous: A type called

Suspension

• A suspension is a cloudy mixture in which clumps of a solid or droplets of a liquid are scattered throughout a liquid or gas.

• Muddy water, tomato juice, and orange juice with pulp are suspensions.

• The parts of a suspension may separate into layers if the suspension is not stirred.

Fresh Milk from the cow is a

suspension

• Farm-fresh milk

is a suspension.

If the milk is left

standing, the

fatty part (the

cream) floats to

the top and the

watery part sinks

to the bottom.

What about commercial milk?

• Commercially available milk does not separate. It is a special kind of suspension, called an emulsion, which has been treated to keep it from separating.

• In a process called homogenization, the milk is sprayed through very small openings. This breaks down the fat into droplets that are so tiny they stay suspended and NOT separate.

Classify the following as heterogeneous (suspension,

mechanical) or homogeneous (solution)

• Brass is made of copper

and zinc.

• They are not chemically

combined.

• Brass is a

compound/mixture.

• Brass is a homogeneous

mixture (solution)/

Heterogeneous mixture. A mixture of solids is called an

ALLOY


mechanical), homogeneous (solution), or pure substance





Cu







NaCl

Element Compound

Ca CaCl2 H2O Na O2Cl2 NaCl

Classifying Matter

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