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Chapter 2 – section one - Composition of Matter

Atoms are matter.
Everything in the universe is made up of matter.
Matter is anything that has mass and takes up space
Chemistry is the scientific study of the composition, structure, and properties of matter and the changes that matter undergoes.
Element a substance that cannot be separated or broken down into simpler substances by chemical means
Atom the smallest unit of an element that maintains the properties of that element
Elements combine chemically to form a compound.
Compound a substance made of atoms of two or more different elements that are chemically combined
Compounds have unique properties.
Every compound is different from the elements it contains.
When elements combine to form a specific compound, they always combine in the same proportions.
A molecule acts as a unit.
Atoms can join together to make millions of molecules.
Molecules are the smallest unit of a substance that keeps all of the physical and chemical properties of that substance.
Chemical formulas represent compounds and molecules.
A chemical formula shows how many atoms of each element are in a unit of a substance.
Chemical formula a combination of chemical symbols and numbers to represent a substance.

Pure Substances and Mixtures

Pure substance a sample of matter, either a single element or a single compound, that has definite chemical and physical properties

Mixture a combination of two or more substances that are not chemically combined

Mixtures are classified by how thoroughly the substances mix .

Heterogeneous mixture substances aren’t mixed uniformly and are not evenly distributed

Homogeneous mixture substances are evenly distributed, and the mixture is the same throughout (homogenized milk)

Gases can mix with liquids.