Matter
Pure substances
Pure substance: Matter that always has the exact same composition
KEY: Every sample of a given substance has the same properties because a substance has a fixed, uniform composition.
Elements
Compounds
Element: a substance that cannot be broken down into simpler substances
Atom: the smallest particle of any given element
KEY: an element has a fixed composition because it contains only one type of atom.
No two elements contain the same type of atom
Examples
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-Aluminum foil
-Soda cans (most made of aluminum)
-Pencil lead (contains carbon)
-Oxygen, nitrogen, bromine, mercury
Symbols
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Created by: Jons Berzelius in 1813
First letter always capitalized
2nd letter (if any) never capitalized
Letters were chosen based on the Latin names of elements
Compound: A substance that is made from two or more substances and can be broken down into simpler substances.
KEY: compound always contains two or more elements joined in a fixed proportion
Mixtures
KEY: The properties of a mixture can vary because the composition of a mixture is not fixed.
Heterogeneous mixtures
Heterogeneous mixture: the parts of the mixture are noticeably different from one another.
Homogeneous mixtures
Homogeneous mixture: the substances are so evenly distributed that is hard to distinguish one substance in the mixture from another.
Solutions, suspensions, and Colloids
KEY: Based on the size of its largest particles, a mixture can be classified as a solution, a suspension, or a colloid.
Solutions
Solutions: what happens when substances dissolve and form a homogeneous mixture, the mixture that forms is a solution
suspensions
Suspension: A heterogeneous mixture that separates into layers over time.
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