The Classification of Matter: Atoms, Elements, Molecules and Compounds

Chemistry: The study of matter and its changes Matter: Anything that has mass and volume

Atom: The basic unit of matter Element: A type of atom

Each element has a name and symbol:

Not all elements are equally common

Kinetic Molecular Theory Matter is made of tiny particles called atoms, which combine to form molecules.

Molecule: A group of atoms held together by sharing electrons (covalent bonds) Compound: A substance containing more than one element.

Examples: Atom, Element, Molecule, Compound:

Four different molecules: Which are compounds?

Some molecules are more complex: Some fat molecules: A protein molecule: cholester ol

What are each of these? Atom, Element, Molecule, or Compound

Allotropes One of several different forms of an element O 2 Diatomic Oxygen Molecule O Monatomic Oxygen (Single Oxygen Atom) O 3 Ozone Molecule Oxygen has 3 allotropes:

Allotropes of Carbon Carbon Nanotubes Fullerenes GraphiteDiamond All are pure carbon; each has a different molecular or crystalline form.

Practice with Vocabulary:

Molecules can be represented many ways: Chemical Formula: Structural Formula: CH 4 H 2 O Ball and Stick Model: Space Filling Model: H H O

Chemical Formula: All molecules can be represented by a H2OH2O subscript

Chemical Formulas show how many atoms of each element are in one molecule: 6234 C 6 H 12 O 4 Cl 3123 C3H8OC3H8O 032 H2OH2O 021 O2O2 # of Carbon atoms # of atoms total # of elements Chemical Formula

How many atoms of each element are present in one molecule of: (NH 4 ) 2 SO 3 N……………. H…………… S……………. O…………… (NH 4 ) 2 SO How many atoms of each element are present in one molecule of: (NH 4 ) 2 SO How many atoms of each element are present in one molecule of: (NH 4 ) 2 SO

The Classification of Matter: Pure Substances and Mixtures

Pure Substance: = An element or a compound (Any substance that can be described by a single chemical formula) Mixture: A substance that contains more than one pure substance Pure Substance: = An element or a compound (Any substance that can be described by a single chemical formula) Mixture: Pure Substance: = An element or a compound (Any substance that can be described by a single chemical formula) A substance that contains more than one pure substance Mixture: Pure Substance: = An element or a compound (Any substance that can be described by a single chemical formula)

Pure Substance or Mixture?

Pure Substances: Are made of only one compound or one element. Can be represented by one chemical formula. Examples : Salt NaCl Copper Cu Water H2OH2O Pure Substances: Salt Pure Substances: Salt Pure Substances: Copper Salt Water Copper Salt Water Copper Salt

Anything that contains more than one pure substance. Mixture: Examples : Juice, Granite, Salad Dressing, etc… Anything that contains more than one pure substance. Mixture: Examples : Anything that contains more than one pure substance. Mixture: Juice, Granite, Salad Dressing, etc… Examples : Anything that contains more than one pure substance. Mixture:

Homogenous Mixture An even mixture; particles are blended evenly throughout the mixture. (= solutions) Heterogeneous Mixture: An uneven mixture; particles are unevenly distributed.

A. Matter Flowchart MATTER Can it be physically separated? Homogeneous Mixture (solution) Heterogeneous MixtureCompoundElement MIXTUREPURE SUBSTANCE yesno Can it be chemically decomposed? noyes Is the composition uniform? noyes ColloidsSuspensions

Pure Substance: A substance that contains only one type of atom or molecule Mixture: A substance that contains more than one pure substance

Single Chemical Formula: All pure substances can be represented by a H2OH2O If its really a pure substance, you should only need to write ONE chemical formula to describe its composition.

Distillation

Vacuum Filtration Electrolysis