There are two kinds of pure substances: elements and compoundsElements are made up of only one type of atom. Examples are copper, aluminum, and hydrogen. All the elements discovered thus far are shown in a periodic table.
Compounds are made of two or more elements or atoms. Examples are water, hydrogen peroxide and table sugar. The ratio of the elements in a given compound is fixed. For example, the ratio of hydrogen to oxygen in water is 2 atoms of hydrogen to 1 atom of oxygen. In hydrogen peroxide, hydrogen and oxygen are also combined, but the ratio is 2 atoms of hydrogen to 2 atoms of oxygen. Water and hydrogen peroxide are different compounds with different properties.
Classification Of Matter
Classification of Matter<br />Rhodora Snow Ph.D.<br />
Definition of Matter<br />Has mass and occupies space<br />Examples<br />Water<br />Wood<br />Plastic<br />
Classification of Matter<br />Pure Substances<br />Fixed Composition<br />Mixtures<br />Variable Composition<br />Howdoyouturnthison. A plate of dolly mixture. 29 July 2008. http://commons.wikimedia.org/wiki/File:Dolly_mixture.JPG<br />
Kinds of Pure Substances<br />Elements <br /><ul><li>One type of atom
All discovered elements are listed in a periodic table</li></ul>Accordion Guy. Periodic Table of Google Images. September 2006.<br />http://www.neatorama.com/2006/09/24/<br />
Kinds of Pure Substances<br />Compounds<br /><ul><li>Made of two or more elements in a fixed ratio
Benjah-bmm27, Hydrogen peroxide. 5 May 2007. http://commons.wikimedia.org/wiki/File:Hydrogen-peroxide-3D-vdW.png</li></li></ul><li>Elements and Compounds <br />Compounds may be separated into its component elements.<br />Example<br />Electrolysis of water <br />General Chemistry students of University of Siegen [photographer], Public Domain, http://upload.wikimedia.org/wikipedia/commons/7/78/Elektrolyse1.jpg<br />
Mixtures <br /><ul><li>Two or more substances physically mixed
Steel (mixture of iron, nickel, carbon abd chromium)
Sugar-Water (two mixtures may look the same but one could taste sweeter because it has a higher ratio of sugar to water)</li></li></ul><li>Kinds of Mixture<br />Homogeneous<br /><ul><li>small particles