MATTER: MIXTURES AND ELEMENTS AND

COMPOUNDS

You will distinguish between physical and chemical propertiesYou will classify matter by composition.You will explain the fundamental law of the conservation of

mass

WHAT YOU’LL LEARN

A mixture is a combination of two or more substances in which each pure substance retains its individual chemical properties

This is a physical blending, not a chemical blending.

Composition of the mixture can vary Can be physically separated

MIXTURES

Heterogeneous Mixture- one that does not blend smoothly throughout and which the individual substances remain distinct

Examples: Sand and Water, Oil and Water, Cement

Homogeneous Mixture (Solutions)- has constant composition throughout; it always has a single phase

Examples: salt water, vinegar, alloys

HETEROGENEOUS VS. HOMOGENOUS

MagnetFilterDecantEvaporationCentrifugeChromatographyDistillation

METHODS OF SEPARATING MIXTURES

A technique that uses a porous barrier to separate a solid from a liquid

FILTRATION

A technique that is based on differences in the boiling points of substances

DISTILLATION

A technique that results in the formation of pure solid particles of a substance from a solution containing the dissolved substance

CRYSTALLIZATION

A technique that separates the components of a mixture on the basis of the tendency of each to travel or be drawn across the surface of another material

CHROMATOGRAPHY

Elements- are the simplest form of matter that can exist under NORMAL laboratory conditions Cannot be separated into simpler substances by chemical means

Are the building blocks for all other --substances

Compounds-are substances that can be separated into simpler substances by chemical means

ELEMENTS AND COMPOUNDS

Elements comprising compounds combine in definite proportions

Regardless of the amount, a compound is always composed of the same elements in the same proportion by mass

LAW OF DEFINITE PROPORTIONS

Water Methane

Percent by Mass- the ratio of the mass of each element to the total mass of the compound as a percentage

PERCENT BY MASS

x100compound of mass

element of mass(%) massby percent

A 78.0g sample of an unknown compound contains 12.4 g of hydrogen. What is the percent by mass of hydrogen in the compound?

PRACTICE PROBLEM

100x78.0g

12.4gmassby Percent

15.9% Hydrogen

MORE PRACTICE

Material Pure Substance or Mixture

Element, Compound, Homogeneous, Heterogeneous

Limestone (CaCO3)

Air

Bronze

Copper

Sugar + water

Concrete

Pure Water

Caffeine

Material Pure Substance or Mixture

Element, Compound, Homogeneous, Heterogeneous

Limestone (CaCO3) PURE SUBSTANCE COMPOUND

Air MIXTURE HOMOGENEOUS

Bronze MIXTURE HOMOGENEOUS

Copper PURE SUBSTANCE ELEMENT

Sugar + water MIXTURE HOMOGENEOUS

Concrete MIXTURE HETEROGENEOUS

Pure Water PURE SUBSTANCE COMPOUND

Caffeine PURE SUBSTANCE COMPOUND

MORE PRACTICE!

SUMMARY

MATTER

MatterMatter

SubstanceDefinite composition

(homogeneous)

SubstanceDefinite composition

(homogeneous)

Element(Examples: iron, sulfur,

carbon, hydrogen,oxygen, silver)

Element(Examples: iron, sulfur,

carbon, hydrogen,oxygen, silver)

Mixture ofSubstances

Variable composition

Mixture ofSubstances

Variable composition

Compound(Examples: water.

iron sulfide, methane,aluminum, silicate)

Compound(Examples: water.

iron sulfide, methane,aluminum, silicate)

Homogeneous mixtureUniform throughout,also called a solution

(Examples: air, tap water,gold alloy)

Homogeneous mixtureUniform throughout,also called a solution

(Examples: air, tap water,gold alloy)

Heterogeneous mixtureNonuniform

distinct phases(Examples: soup, concrete, granite)

Heterogeneous mixtureNonuniform

distinct phases(Examples: soup, concrete, granite)

Chemicallyseparable

Physicallyseparable

Read Oobleck Lab-There will be a QUIZ before the lab over what you will be doing!

Make sure you bring the lab back-you will not receive another one. =)

Book work: PAGE 69: 15-17 PAGE 76: 21-23 PAGE 77: 25-27, 30

HOMEWORK =)

Work on Classifying Matter Worksheet If you finish-read Oobleck Lab

FOR THE REMAINDER OF CLASS