physical and chemical changes. properties of matter all pure substances have characteristic...
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Physical and Chemical Changes
Properties of Matter•All pure substances have
characteristic properties
•Properties are used to distinguish between substances
•Properties are also used to separate substances
Physical Properties
•A Physical Property is a characteristic that can be observed or measured without changing the composition of the substance
•Physical properties describe the substance itself
•Examples▫Changes of State▫Color▫Mass, shape, length▫Magnetic properties
States of Matter•There are three common states of matter: solid, liquid, and gas
Solids•Definite shape and definite volume•Particles are packed tightly together and held in fixed positions
•Particles vibrate about fixed points
Liquids•Definite volume•Takes the shape of its container
▫Example: Milk in a glass vs. Milk in a gallon jug
•Particles can move past each other (fluid)▫Fluid – Anything that can be poured
•Particles move more rapidly than in a solid
Gases•No definite shape, takes the shape of
its container•No definite volume•Particles are spread far apart and move
past each other rapidly
Chemical Properties•A Chemical Property
indicates how a substance will react with another
•Chemical properties cannot be determined without changing the identity of the substance
•Examples:▫Iron Rusting▫Silver Tarnishing
Physical Changes•A Physical Change is a change in a
substance that does not alter the substance’s identity▫Examples:
Grinding Cutting Melting Boiling
Chemical Changes•A change in which one or more
substances are converted into different substances is called a Chemical Change
•Signs of a Chemical Change:▫Color Change▫Gas is Released▫Temperature Change▫Precipitate – Solid falls out of solution▫Substance Disappears
Intensive vs. Extensive Properties•Extensive properties depend on
the amount of matter that is present▫Examples: Energy in a substance,
Volume, Mass
• Intensive properties do not depend on the amount of matter present▫Examples: Density, Melting Point,
Boiling Point
Qualitative vs. Quantitative Measurements
•Qualitative measurements are descriptive▫Examples:
Physical State, Color, Shape, Sound, Smell
•Quantitative measurements are numerical▫Examples:
Length, Mass, Volume, Density
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