CHE Q1 Lesson 4: Classification of Matter

Mixtures

They are combinations of two or more substances that can be separated by physical methods.

They have variable compositions.

Can be classified as homogenous and heterogeneous.

Homogenous and Heterogeneous

Classifications of Mixtures

Mixtures

They are combinations of two or more substances that can be separated by physical methods.

They have variable compositions.

Can be classified as homogenous and heterogeneous.

Homogenous and Heterogeneous

Classifications of Mixtures

Homogenous Mixture

It has uniform composition and properties as seen by the naked eye. Examples are seawater and air. These are also called SOLUTIONS

Heterogeneous Mixture

It is not uniform in composition. Consists of two or more phases.

Phase

Any part of a system with uniform composition and particles.

Suspensions

These are heterogeneous mixtures where the suspended particles can be seen and large enough to be filtered.

Colloids

These are generally classified as heterogeneous mixtures where the particles are bigger than those of solutions but smaller than those of suspensions.

Coarse mixtures

These are heterogeneous mixtures where the particles can be seperared mechanically.

Suspensions

Colloids

Coarse mixtures

Types of Heterogeneous Mixtures.

Decantation

Flotation

Centrifugation

Distillation

Fractional distillation

Crystallization

Fractional crystallization

Chromatography

Separating Mixtures

Decantation

Pouring of the liquid from a mixture to seperate the liquid (decantate) from the solid particles.

Filtration

The pouring of a mixture through a piece of paper (filter paper) which lets the liquid (filtrate) pass through but catches the solid.

Distillation

This makes use of the differences in boiling points.

In a mixture of two liquids, the liquid with the lower boiling point boils and changes info gas first. The gas is then condensed back into a liquid.

Fractional distillation

This seperates liquid mixtures whose components have boiling points that differ by just a few degrees. This process is used in petroleum refineries.

Crystallization

This occurs when simple saltwater is allowed to evaporate.

Fractional crystallization

This involves lowering the temperature of solutions so that the more metal component crystallizes out first.

Chromatography

A solution is seperated by allowing it to flow along a stationary substance.

Element

A substance that cannot be broken down into simpler substances by a chemical change.

118 known elements

How many elements are there?

94 elements

Number of elements that occur naturally on the earth.

24 elements

Number of elements that have been produced artificially.

Chlorus

Greek for greenish yellow

Arnum (GOLD)

Latin for shiny

Metals, Nonmetals, and Metalloids

The 3 groups of elements

Compounds

These are formed when two or more elements combine in a chemical change. They are substances that can be broken down into simple substances only by a chemical reaction.

Aspirin

Common analgesic that is derived from willow tree barks.

Taxol

A cancer drug for ovarian and breast tumors.