2.1. Properties of Matter http://www.ck12.org
Description of Matter
Recall that matter is considered to be anything that has mass and occupies space. Matter can be best understood in
terms of its properties. Some properties of matter can be determined without altering the identity of the matter, and
it is there that we will begin.
Physical Properties
Pictured in theFigure2.1 are two very different objects. Each has a different chemical composition, meaning that
each is made up of a different type of matter.
FIGURE 2.1
(A) This lamp from the country of Sri
Lanka is made of silver. (B) These large
salt mounds from Bolivia were produced
during a salt mining operation.Silver and ordinary table salt are two examples of chemical substances. Apure substanceis matter that has a
uniform and definite composition. All samples of pure substances have identical properties.
Aphysical propertyis a characteristic of a substance that can be observed or measured without changing the
identity of the substance. For example, silver is a shiny metal that conducts electricity very well. It can also be
molded into thin sheets, a property called malleability. These are all physical properties of silver. In contrast, salt
is dull and brittle, but it can also conduct electricity after being dissolved in water, which it does quite readily. In
addition to color, hardness, malleability, solubility, and electrical conductivity, some other physical properties of
matter include density, melting point, and boiling point.
There are many examples of physical properties that can be further investigated on the internet.
- Magnetism is a physical property. Are all metals magnetic? Find out at http://www.youtube.com/watch?v=iK-5
-BRLn78. - You can view a video of the melting points of various substances at http://www.youtube.com/watch?v=NYb2iTNF
CsI. - Do you think metals like lead melt easily? Check out this alloy containing lead melting in boiling water: http://www.
youtube.com/watch?v=JI9qKbQCukg. - The physical property density can be observed by floating bubbles on carbon dioxide. Watch the video at
http://www.youtube.com/watch?v=h3EWYrxrsns.
Extensive and Intensive Properties
Some properties of matter depend on the size of the sample, while some do not. Anextensive propertyis a property
that depends on the amount of matter in a sample. Themassof an objectis a measure of the amount of matter that
an object contains. A small sample of a certain type of matter will have a small mass, while a larger sample will