Classifying MatterClassifying Matter

Matter

ElementsCompound

sMixtures

• Scientists classify matter according to make-up.

ElementsElements

• Simplest pure substance – fixed composition.

• Pure substance is made of only one material. Same throughout. Referred to as homogeneous matter.

• Are made of alike atoms, which are the basic building blocks of matter.

• Represented by chemical symbols - H, O, Al, Cu, Au.

• 118 elements organized in the periodic table in squares called an element key.

Element KeyElement Key

Atomic Number

Symbol

Element Name

Atomic Mass

I.D’s the element

represents elements

mass of element (amu’s)

• Calcium• Tin• Uranium• Magnesium• Phosphorus• Iron• iodine• Silver• Helium• Mercury

• Nickel• Silicon• Sulfur• Copper• Chromium• Aluminum• Bromine• Hydrogen• Zinc• Potassium

Elements/Symbols Elements/Symbols

• Oxygen• Lead• Lithium• Gold• Fluorine• Neon• Nitrogen• Sodium• Carbon• Chlorine

CompoundsCompounds

• Two or more elements chemically combined.

• Represented by chemical formulas.

• Examples: H2O, CO2, NaCl, C12H22O11

• Molecules are the smallest natural unit of a compound or diatomic element. A molecule is made up of two or more atoms chemically combined.

Chemical FormulasChemical Formulas• Combination of chemical symbols that represents compounds.

• Sometimes represents a molecule of an element. Example: O2, N2, Cl2 called diatomic elements – two atoms of the same element.

• Subscripts are the # of atoms of an element - H2O

• Coefficients are the # placed in front of chemical formula. Represents # of molecules of a compound - 4 H2O

Identifying SubstancesIdentifying Substances

Substance

Element or

Compound

Symbol or

Formula

Atom or

Molecule

Fluorine (F)

Water (H2O)

Chlorine gas (Cl2)

Element Symbol

Atom

Compound

Formula

Formula

Molecule

Element

Molecule

Counting AtomsCounting Atoms

Name Use FormulaAtoms in Formula

Calcium carbonate

Chalk CaCO3

Magnesium hydroxide

Found in milk of

magnesia

Mg(OH)2

Phosphoric acid

Detergents

3H3PO4

Trinitrotoluene (TNT)

Explosive

2C7H5(NO2)3

Ca=1C=1O=3

H=9

P=3

O=12

Mg=1

O=2

H=2

C=14 N=6

H=10 O=12

Calculating Formula Mass

Calculating Formula Mass

• Formula mass of a compound is the sum of the atomic weights of all atoms in a chemical formula.

• Examples: Atoms Atomic Mass Totals

H2O 2 of H 2 x 1.02.0

1 of O 1 x 16.016.0

18.0 amu

C12H22O11 12 of C 12 x 12.0144.0

22 of H 22 x 1.0 22.0

11 of O 11 x 16.0 176.0

342.0 amu

MixturesMixtures

• Two or more substances mixed together but not chemically combined.

• Has unlike parts and a composition that varies from sample to sample.

• Properties:

– Sub. in a mixture keep their separate identities.

– Sub. can be present in any amount.

– Sub. can be separated out by physical means.

MixturesMixtures

Mixtures

Homogeneous Heterogeneous

Heterogeneous Mixtures

Heterogeneous Mixtures

• The least-mixed.• Doesn’t appear to

be the same throughout.

• Particles large enough to be seen.

• Examples: sand, dirt, concrete, suspensions, etc.

Homogeneous MixturesHomogeneous Mixtures

• Well-mixed. Same throughout a given sample.

• Examples: air, soda, toothpaste, lotions, etc.

SolutionsSolutions

• A homogeneous mixture.

• One substance dissolves in another. Solutions remain constantly & uniformly mixed.

• Examples: lemonade, soda, ocean water, antifreeze, metal alloys (steel, brass), etc.

ColloidsColloids

• A homogeneous mixture.

• Mixed together but not dissolved.

• Appears cloudy. Scatters light.

• Examples: milk, cool whip, toothpaste, lotions, fog, paint, etc.

Composition of MatterComposition of Matter

E lem e nt C o m p ou nd

P u re S u bs tan ce

S o lu tion C o lliod

H o m o ge n eo us

S usp en sion

H e te rog en eo us

M ixtu re

M atte r