ChemistryWiki | RecentChanges | Preferences
Matter refers to all the materials found in nature. It is classified into three groups:
- elements
- compounds
- mixtures
Any sample of either an element or a compound has the same properties as any other sample of the same element or compound
- A substance is a kind of matter, all samples of which have the same properties, or characteristics (these are explained later)
Element
- a substance that cannot be broken down into other substances by ordinary chemical change
Compound
- a substance made up of two or more elements chemically combined
- can be broken down by a chemical change
- the elements making up a compound are combined in a definite proportion by mass (ratios)
- the chemical and physical properties of a compound differ from those of its constituents
- compounds can be formed and broken down into simpler substances by chemical change
Mixtures
- consists of two or more substances, each of which retains individual properties
- can be formed when:
- an element is mixed with one or more other elements
- a compound is mixed with one or more other compounds
- one or more elements are mixed with one or more compounds
- a mixture retains the properties of each of its constituents (this characteristic helps to separate a mixture into its constituents)
- the composition of a mixture can vary widely and is not fixed as in an element or compound
- mixtures are either heterogeneous (a sample of matter with different compositions) or homogeneous (same throughout but can be different for different samples)
Examples
- Elements- everything on the Periodic Table, so oxygen, silver, nitrogen
- Compounds- sugar, water
- Mixtures- Kool - Aid is homogeneous, while chocolate swirl ice cream is heterogeneous
<b>Modified 5/05 - Mr. McLeod