What’s the MATTER, part II

Types of Matter

Pure Substance- Matter with a fixed composition It has distinct properties Examples = elements

compounds

Pure substance = Only ONE element or compound (distilled water). Pure substance = Only ONE element or compound (distilled water).

Some Examples:

Mixtures- Most matter is a mixture The composition is not fixed (changes

from sample to sample) Two Types –

HomogeneousHeterogeneous

Some Examples:

Mixtures are variable combinations of 2 or more pure substances.

Heterogeneous –visibly separate phases

Homogeneous – Same throughout

Air is a mixture of several gases.

Name Formula amount

Nitrogen N2 78 %

Oxygen O2 21 %

Argon Ar 1 %

Carbon CO2 0.03 %

Dioxide

Homogeneous Mixtures

Composition is uniform throughout Solution-

Particle size = 0.01 – 1 nm Doesn’t settle out upon standing Can’t be separated by filtering Doesn’t scatter light Example = distilled water

Colloid- Particle size = 1 – 1000 nm Doesn’t settle out upon standing Can’t be separated by filtering Scatters light (Tyndall Effect) Examples = milk, gelatin, smoke

Heterogeneous Mixtures

The sample varies in composition, properties and appearance

No uniformity Particle size is greater than 1000 nm Particles settle out upon standing Can be separated by filtration Might scatter light Examples = soil, trail mix, pond water

Physical vs. Chemical Properties

Every substance has a unique set of properties (characteristics that identify that substance)

Physical Properties- Properties that can be measured without

changing the identity and composition of the substance

Physical Property Examples- Color Odor Density Melting Point Boiling Point Hardness Solubility

Physical Change

A change in matter from one form to another without changing its chemical properties (most can be reversed)

Examples = Change in state Dissolving Compressing

Chemical Properties

Properties that describe the way a substance may change to form other substances

Only observed when a chemical reaction takes place

Chemical Property Examples

Heating to combustion Reactivity with water or acid Flammability Corrosion Decomposition

Law of Conservation of Mass

In a physical change or a chemical reaction, mass is neither created or destroyed

(Antoine Lavoisier)

Is the composition uniform?

NoYes

MATTER

Can it be physically separated?

Homo-geneous Mixture

(solution)

Hetero-geneous Mixture Compound

MIXTURE PURE SUBSTANCE

Yes No

Can it be chemically decomposed?

NoYes

Suspensions

Element

Colloids

Putting sand and salt together makes

a compound.

an element.

a mixture.

a solution.

Pure Water is

a compound.

an element.

a solution.

a mixture.

Pure Water is

a compound.

an element.

a solution.

a mixture.

Tap Water is

a compound.

an element.

a solution.

a mixture.

Tap Water is

a compound.

an element.

a solution.

a mixture.

Salt (NaCl) is a common substance. Salt is which of these?

atom

element

compound

mixture

Salt (NaCl) is a common substance. Salt is which of these?

atom

element

compound

mixture

Which formulas represent compounds?

O2, H2O2

CO2, H2O

H2, CO2

H2, O2

Which formulas represent compounds?

O2, H2O2

CO2, H2O

H2, CO2

H2, O2

Which of the following is a compound?

• oxygen

• water

• nitrogen

• air