Chapter 2Atoms and Elements 2.1 Classification of Matter Copyright © 2007 by Pearson Education,...

Chapter 2 Atoms and Elements

2.1Classification of Matter

Copyright © 2007 by Pearson Education, Inc.Publishing as Benjamin Cummings

A pure substance is classified as Matter with a specific composition.

An element when composed of one type of atom.

A compound when composed of two or more elements chemically combined in a definite ratio.

Pure Substances

Elements

Elements are Pure substances that

contain atoms of only one type.

Copper Cu

Lead Pb

Aluminum Al Copyright © 2007 by Pearson Education, Inc.Publishing as Benjamin Cummings

Compounds

Compounds Contain two or more

elements bonded together in a definite ratio.

Salt (NaCl)

Table sugar (C12H22O11)

Water (H2O)


Elements in a Compound

“Table salt” is a compound that contains the elements sodium and chlorine.


Reaction

Identify each of the following as a pure substance or a mixture.

A. pasta and tomato sauce

B. aluminum foil

C. helium

D. air

Learning Check

Identify each of the following as a pure substance or a mixture.

A. pasta and tomato sauce mixture

B. aluminum foil pure substance

C. helium pure substance

D. air mixture

Solution

Mixtures

A mixture is matter that consists of Two or more substances that are physically

mixed, not chemically combined. Two or more substances in different proportions. Substances that can be separated by physical

methods.

Homogeneous Mixtures

In a homogeneous mixture,

The composition is uniform throughout.

The different parts of the mixture are not visible.


Heterogeneous Mixtures

In a heterogeneous mixture,

The composition is not uniform, it varies from one part of the mixture to another.

The different parts of the mixture are visible.


Identify each of the following as a homogeneous orheterogeneous mixture:

A. hot fudge sundae

B. shampoo

C. sugar water

D. peach pie

Learning Check

Identify each of the following as a homogeneous orheterogeneous mixture:

A. hot fudge sundae heterogeneous mixture

B. shampoo homogeneous mixture

C. sugar water homogeneous mixture

D. peach pie heterogeneous mixture

Solution

Physical Separation of A Mixture

The physical separation of a mixture Involves only physical changes. Occurs when is pasta and water are separated

with a strainer.


Chapter 2Atoms and Elements 2.1 Classification of Matter Copyright © 2007 by Pearson Education,...

Documents

Transcript of Chapter 2Atoms and Elements 2.1 Classification of Matter Copyright © 2007 by Pearson Education,...