Introduction to Matter

All Matter Has Three Major Characteristics: G 1. It has mass G 2. It occupies space G 3. It is made of particles (atoms) G 1. It has mass G 2. It occupies space G 3. It is made of particles (atoms)

The word atom G Originates from the Greek atomos, meaning indivisible.

Not All Atoms are Identical

….or Natural G Of all the elements on the Periodic Table (Currently, around 110)… G Only 90 exist in nature, the rest are by-products of nuclear reactors G Of all the elements on the Periodic Table (Currently, around 110)… G Only 90 exist in nature, the rest are by-products of nuclear reactors

Atoms can Combine G In whole number ratios to form compounds G Common compounds include H 2 O and NaCI (water and salt)

G An atom is the smallest particle of a particular element G A molecule is the smallest particle of a compound. G An atom is the smallest particle of a particular element G A molecule is the smallest particle of a compound.

Matter exists in three states G SOLID G LIQUID G GAS G A fourth state called PLASMA exists, but is rare on Earth

G Solids: Fixed shape, fixed volume G Liquids: Variable shape, fixed volume G Gases: Variable shape and volume G Solids: Fixed shape, fixed volume G Liquids: Variable shape, fixed volume G Gases: Variable shape and volume

Matter has Properties Physical Properties: State of matter, appearance, density, smell, etc. Chemical Properties: Reacts with… Physical Properties: State of matter, appearance, density, smell, etc. Chemical Properties: Reacts with…

Matter can undergo changes G These changes can be physical changes G Or chemical changes G These changes can be physical changes G Or chemical changes

Physical Changes Involve a change a change in state, But…Do NOT change the identity of the substance (Boiling water is still H 2 O)

Chemical Changes Are observed only during chemical reactions… Where the composition of matter changes Are observed only during chemical reactions… Where the composition of matter changes

All Matter Fits into one of Two General Categories: G Pure Substances G Mixtures

Pure Substances G Elements or compounds G Have uniform composition (can not be separated by physical means) G Pure water is H 2 O, pure Gold consists of just Gold atoms G Elements or compounds G Have uniform composition (can not be separated by physical means) G Pure water is H 2 O, pure Gold consists of just Gold atoms

Mixtures G Have variable compositions G Mixtures can be separated by Physical means (filtration or distillation) (Lab Techniques: Sand and Salt water)

Mixtures can be… Homogeneous: same throughout (salt water, air, brass) Heterogeneous: vary from region to region (sand and water, gravel) Homogeneous: same throughout (salt water, air, brass) Heterogeneous: vary from region to region (sand and water, gravel)

G Classification of Matter Chart Classification of Matter Chart G Classification of Matter Chart Classification of Matter Chart

Other Sub-classes of Mixtures G Colloids: a type of mixture with particles of larger size than a true solution… G Will exhibit Tyndall Effect G Will NOT settle

Why is the sky Blue? G Rayleigh scattering

Other Sub-classes of Mixtures G Suspension: Similar to a colloid, but with larger particles G Will settle if left undisturbed G Suspension: Similar to a colloid, but with larger particles G Will settle if left undisturbed