15 Table of Contents 15 Chapter 15: Classification of Matter 15.1: Composition of MatterComposition of Matter 15.2: Properties of MatterProperties of

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Table of ContentsTable of Contents

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Chapter 15: Classification of Matter

15.1: Composition of Matter

15.2: Properties of Matter

Unit 4: The Nature of Matter

• All substances are built from atoms. • element – Pure Substance- all the atoms in a

have the same identity

• Examples: ?

Elements15.115.1Composition of MatterComposition of Matter

• About 90 elements are found on Earth.

• More than 20 others have been made in laboratories, but most of these are unstable and exist only for short periods of time.

Elements15.115.1Composition of MatterComposition of Matter

• Examples?

Compounds15.115.1Composition of MatterComposition of Matter

• Compound- two or more elements combine to form substances (has a specific chemical composition)

Compounds15.115.1Composition of MatterComposition of Matter

• A mixture- Material made up of two or more substances that can be easily separated by physical means.

• Examples?

Mixtures15.115.1Composition of MatterComposition of Matter

Heterogeneous Mixtures15.115.1Composition of MatterComposition of Matter

• heterogeneous mixture -A mixture in which different materials can be distinguished easily

• Examples?

Heterogeneous Mixtures15.115.1Composition of MatterComposition of Matter

Homogeneous Mixtures15.115.1Composition of MatterComposition of Matter


• Homogeneous mixture two or more gaseous, liquid, or solid substances blended evenly throughout.

• Examples?


• Solution –• (AKA- homogeneous mixture) • Particles cannot be seen with a microscope • Will never settle to the bottom of their

container.

Colloids 15.115.1Composition of MatterComposition of Matter

• colloid -Mixture with particles that are larger than those in solutions but not heavy enough to settle out.

• Not homogeneous or heterogeneous• Examples?

Detecting Colloids 15.115.1Composition of MatterComposition of Matter

• Tyndall effect- scattering of light by colloidal particles

Suspensions 15.115.1Composition of MatterComposition of Matter

• suspension, which is a heterogeneous mixture containing a liquid in which visible particles settle.

• Examples?

Suspensions 15.115.1Composition of MatterComposition of Matter

• The table summarizes the properties of different types of mixtures.

15.115.1Section CheckSection Check

Question 1

A. colloidB. mixtureC. substanceD. solution

A _______ is a type of matter with a fixed composition.


Answer

The answer is C. A substance can be either an element or a compound.


Question 2

A. 5B. 10C. 30D. 90

How many elements are found on Earth?


Answer

The answer is D. About 90 elements are found on Earth, and more than 20 have been made in laboratories.


Question 3

How are compounds different from mixtures?


Answer

The atoms in compounds are combined in fixed proportions and cannot be separated by physical means. A mixture is made of two or more substances that can be easily separated by physical means.

Physical Properties

• physical property - characteristic of a material that you can observe without changing the identity of the material.

• Examples: color, shape, size, density, melting point, and boiling point.

• Item Examples:

Properties of MatterProperties of Matter

15.215.2

Behavior 15.215.2


Physical Change 15.215.2


• physical change -A change in size, shape, or state of matter.

The Identity Remains the Same

• Examples?

15.215.2Properties of MatterProperties of Matter

The Identity Remains the Same


Using Physical Change to Separate

• Distillation- Separating substances in a mixture by evaporating a liquid and recondensing its vapor


Distillation


Chemical Properties and Changes

• chemical property- characteristic of a substance that indicates whether it can undergo a certain chemical change.

• Examples?


• If you leave a pan of chili cooking unattended on the stove for too long, your nose soon tells you that something is wrong.

Detecting Chemical Change

• This burnt odor is a clue telling you that a new substance has formed.


• chemical change - A change from one substance to another

The Identity Changes

• Indications of chemical change: • Odor• Temperature Change• Formation of gas/solid• Color

Click image to view movie


The Conservation of Mass


• no mass is lost during a chemical or physical reaction.

The Conservation of Mass

• Law of conservation of mass, the mass of all substances equal the mass of all the substances that remain after the change.


Question 1

A. boiling pointB. densityC. flammabilityD. melting point

Which of the following is a chemical property?


Answer

The answer is C. Flammability indicates whether a substance will undergo the chemical change of burning.


Question 2

A characteristic of a material that can be observed without changing the identity of the substances that make up the material is a _______.


Answer

The answer is physical property. Examples of physical properties include color, shape, and density.


Question 3

What is the law of conservation of mass?


Answer

According to the law of conservation of mass, the mass of all substances that are present before a chemical change equals the mass of all substances that remain after the change.

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15 Table of Contents 15 Chapter 15: Classification of Matter 15.1: Composition of MatterComposition of Matter 15.2: Properties of MatterProperties of