SOLUTIONS

MIXTURES

MATTER

COMPOUNDS

PURE SUBSTANCES

ELEMENTS

SUSPENSIONSORDINARY MECHANICAL

MIXTURES

Physical change

Chemicalchange

COLLOIDS

MECHANICAL MIXTURES

What is a pure substance?What is a pure substance?• A pure substance has a A pure substance has a definite definite

composition (proportion)composition (proportion). .

• The composition of a substance will The composition of a substance will have the same percent of elements no have the same percent of elements no matter where the sample was obtained. matter where the sample was obtained. – Water from the Atlantic Ocean and water Water from the Atlantic Ocean and water

from the Pacific Ocean (once cleaned up) from the Pacific Ocean (once cleaned up) will have the same composition of will have the same composition of hydrogen to oxygen. hydrogen to oxygen.

What is a pure What is a pure substance?substance?•A pure A pure substancesubstance, by , by definition, is an definition, is an element or a element or a compound.compound.

•Salt, Coal, GoldSalt, Coal, Gold

Pure SubstancePure Substance

Pure Substance

Element Compound

What is an What is an elementelement??• A substance that cannot be A substance that cannot be

decomposed any farther by simple decomposed any farther by simple chemical meanschemical means

• An element has a definite An element has a definite composition. composition. Gold from South Africa is Gold from South Africa is the same, when purified, as a sample the same, when purified, as a sample from California.from California.

Chemistry VocabularyChemistry Vocabulary• A A SymbolSymbol is a is a

representation of representation of an element.an element.

• One or two letters One or two letters may be used.may be used.

• The first letter is The first letter is upper case while upper case while the second is the second is lower case.lower case.

H C O

Fe Cl Ag

Cu Ba Pb

Elemental SamplesElemental Samples

•Zinc, copper, lead, carbon, sulfurZinc, copper, lead, carbon, sulfur

What is a compound?What is a compound?•A A compoundcompound is a substance is a substance

that is made from the atoms that is made from the atoms of two or more elements that of two or more elements that are chemically bonded.are chemically bonded.

What is a compound?What is a compound?•A A compoundcompound is a substance that is a substance that

cannot be decomposed any farther cannot be decomposed any farther by simple physical means.by simple physical means.

•A A compoundcompound is made up of two or is made up of two or more elements chemically more elements chemically combined.combined.

What is a compound?What is a compound?•A A compoundcompound no longer has the no longer has the

properties of its constituent properties of its constituent elements.elements.

•Table salt, NaCl or sodium Table salt, NaCl or sodium chloride, is a compound of the chloride, is a compound of the element sodium and the element element sodium and the element chlorine.chlorine.

SodiumSodium

Sodium metalSodium metal•Soft, can be cut Soft, can be cut

with a knifewith a knife•ShinyShiny•Good conductor Good conductor

of electricityof electricity•Very reactiveVery reactive

Sodium in waterSodium in water•Observe the reaction•What is the color of the solution•Do you observe any gas produced•Is it a chemical or physical reaction?•Does the reaction terminate immediately

Chlorine gasChlorine gas

Chlorine gasChlorine gas•Greenish gasGreenish gas•PoisonousPoisonous•Heavier than Heavier than

airair

Sodium in chlorine Sodium in chlorine gasgas

Properties of Sodium Properties of Sodium chloride ( NaCl)chloride ( NaCl)

•Sodium chloride dissolves in water Sodium chloride dissolves in water rather than reacts with water.rather than reacts with water.

•Sodium chloride is a white solid, not Sodium chloride is a white solid, not a poisonous green gas.a poisonous green gas.

•Sodium chloride is its own substance Sodium chloride is its own substance with its own properties, not those of with its own properties, not those of either sodium or chlorine.either sodium or chlorine.

Samples of Other Samples of Other CompoundsCompounds

• Sucrose (table sugar), Sodium Sucrose (table sugar), Sodium Chloride, Water, Copper(II) sulfateChloride, Water, Copper(II) sulfate

Colored CompoundsColored Compounds

• Cobalt(II) chloride, Iron(II) sulfate, Potassium Cobalt(II) chloride, Iron(II) sulfate, Potassium dichromate, Potassium chromate, Nickel(II) dichromate, Potassium chromate, Nickel(II)

nitrate, copper(II) sulfatenitrate, copper(II) sulfate