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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