Describing Matter

Properties of Matter Matter is anything that has mass and

takes up space. Matter can be hard, soft, rough or

smooth, round, square, hot or cold. It can be small enough to fit in your

pocket or as large as the Earth.

States of Matter There are three states of matter: 1. Solid (Ice)2. Liquid (Water)3. Gas (Water Vapor)o https://www.youtube.com/watch?

v=cBBmdqti_Kg

Characteristic Properties Some properties of matter, such as size

or amount, are true only for a given sample of matter.

For example, a piece of ice can be as small as an ice cube or as large as a glacier. The substance is still ice.

Some properties are true for a particular kind of substance no matter what the sample size. These properties are called characteristic properties. (For example, all diamonds have the same hardness.

Since characteristic properties for a given substance never change, they can be used to identify unknown matter.

Boiling Point The temperature at which a liquid boils

is called its boiling point. Boiling point is an example of a

characteristic property of a substance. Boiling points can be an excellent way

to tell one liquid from another. https://www.youtube.com/watch?

v=nVr9WdPjJ-s

Melting Point The temperature at which a solid melts

is called its melting point. Because a solid substance melts at one

temperature only, melting point is another characteristic property.

Checkpoint What are two examples of characteristic

properties?

1. Boiling Point2. Melting Point

Changes in Matter Changes in the state of matter, such as

boiling or melting are examples of physical changes.

There are two types of changes in matter:

1. Physical changes2. Chemical changes

Physical Changes Physical changes change the form of a

substance, but does not change what the substance is. (The pop can is still a pop can, just crushed and the ice is water even when its solid.

Chemical Changes In chemical changes, one or more

substances combine or break apart to form new substances. (Heating sugar and turning into caramel)

When the process is complete, the original sugar particle no longer exists

The ability of a substance to undergo a specific chemical change is another example of a characteristic property.

This property is called the chemical activity of the substance.

Types of Matter Matter can be classified into two general

categories:1. Mixtures2. Pure Substances (elements and

compounds)

Mixtures A mixture consists of two or more

substances that are mixed together but not chemically combined.

In a mixture the individual substances keep their separate properties.

Scientists often classify mixtures by how well they are mixed together.

In mixtures like ocean water (salt water) the parts have been blended so well together that they appear to be a single substance.

This type of mixture is called a solution.

Pure Substances A pure substance is made of only one

kind of matter and has definite properties.

Examples of pure substances are sugar, salt, iron, aluminum and copper.

Every piece of a pure substance is always the same no matter what the form.

Elements Some pure substances called elements

cannot be broken down into other substances by any chemical means.

Individually or in combination, the elements form every object in the world!

Compounds Elements combine in different ways to

form a huge variety of compounds. A compound is a pure substance formed

from chemical combinations of two or more different elements.

An example of a compound is water . Just as symbols are used to represent

elements, formulas are used to represent compounds.

Compound Formulas

The properties of compounds are always different from the properties of the elements that formed them.

REVIEW Using the information you just gathered,

answer the following questions:1. List the three principal states of matter

and give two examples of each2. What is the difference between a

physical change and a chemical change?

3. What is meant by a characteristic property of a substance?