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Introduction to Matter. All Matter Has Three Major Characteristics:. 1. It has mass 2. It occupies space 3. It is made of particles (atoms). The word atom. Originates from the Greek atomos, meaning indivisible. Not All Atoms are Identical. ….or Natural.
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All Matter Has Three Major Characteristics: • 1. It has mass • 2. It occupies space • 3. It is made of particles (atoms)
The word atom • Originates from the Greek atomos, meaning indivisible.
….or Natural • Of all the elements on the Periodic Table (Currently, around 110)… • Only 90 exist in nature, the rest are by-products of nuclear reactors
Atoms can Combine • In whole number ratios to form compounds • Common compounds include H2O and NaCI (water and salt)
An atom is the smallest particle of a particular element • A molecule is the smallest particle of a compound.
Matter exists in three states • SOLID • LIQUID • GAS • A fourth state called PLASMA exists, but is rare on Earth
Solids: Fixed shape, fixed volume • Liquids: Variable shape, fixed volume • Gases: Variable shape and volume
Matter has Properties Physical Properties: State of matter, appearance, density, smell, etc. Chemical Properties: Reacts with…
Matter can undergo changes • These changes can be physical changes • 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 H2O)
Chemical Changes Are observed only during chemical reactions… Where the composition of matter changes
All Matter Fits into one of Two General Categories: • Pure Substances • Mixtures
Pure Substances • Elements or compounds • Have uniform composition (can not be separated by physical means) • Pure water is H2O, pure Gold consists of just Gold atoms
Mixtures • Have variable compositions • 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)
Other Sub-classes of Mixtures • Colloids: a type of mixture with particles of larger size than a true solution… • Will exhibit Tyndall Effect • Will NOT settle
Why is the sky Blue? • Rayleigh scattering
Other Sub-classes of Mixtures • Suspension: Similar to a colloid, but with larger particles • Will settle if left undisturbed