http://www.ck12.org Chapter 2. Matter and Change
2.2 Classification of Matter
Lesson Objectives
- Distinguish between gases, liquids, and solids. Explain how these states differ at the molecular level.
- Classify samples of matter as pure substances, homogeneous mixtures, heterogeneous mixtures, compounds,
and elements. - Use sketches to show how elements, compounds, and mixtures differ at the molecular level.
- Describe six different techniques for separating mixtures.
- Relate the names of elements to their international element symbols.
- Name the major groups and regions on the periodic table and identify elements belonging to these groups.
- Distinguish between metals, nonmetals, and metalloids using the periodic table.
Lesson Vocabulary
- pure substances: Have a constant composition and can only be changed by chemical reactions.
- elements: Substances that cannot be decomposed into simpler substances by chemical or physical means.
- compounds: Substances that can be broken down into their individual elements, but only through chemical
processes. - mixtures: A combination of two or more pure substances.
- homogeneous mixtures: A mixture with uniform composition throughout.
- heterogeneous mixtures: A mixture with visibly distinguishable components, exist primarily in the solid and
liquid states.
Check Your Understanding
- Give some examples of chemical properties and physical properties of matter.
- What would be some chemical and physical properties of the following substances:
- a glass of water
- aluminum foil
- argon
Introduction
As we studied in our last lesson, matter can be described by its physical and chemical properties. We have seen
examples of how matter exhibits specific physical and chemical properties, which can be used to distinguish one
type of matter from another. In this lesson, we are going to use these properties to categorize the various forms of
matter.