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Physical and Chemical
Properties
All substances have properties…
Including people!Example:
People can be identified by their …
Face (shape,
expressions)Voice Height Finger
prints
Eye color Hair color Teeth DNA
What are properties?
• Matter has observable and measurable qualities.
• We can use general properties to identify substances.
• Two basic types of properties of matter: Physical properties and Chemical properties:
Physical properties are used to identify, describe and classify matter.– Characteristic of a substance that can be
observed (using your senses) without changing the substance into something else.
Physical Properties
State Colour Odour Taste
Texture Melting point
Boiling point Density
Physical properties can be classified as qualitative or quantitative.
Physical Properties
Qualitative properties describe matter using words. They cannot be measured or expressed numerically (no numbers involved).• ex. water is colourless, odourless
Physical Properties
Quantitative properties can be measured and expressed numerically (numbers are involved).• ex. the melting point of water is 0°C
Physical Properties
Chemical Properties
• Chemical properties describe how a substance reacts with another substance to form a new substance
Flammability Rusting Reactivity with metals
Reactivity with oxygen
Reactivity with water
Reactivity with acids
Physical & Chemical Change
Physical Changes• do not produce new substances (it’s still
the same substance with same properties)
• involve only one substance (except dissolving)
• are changes in form (powder, crystal, cubes, granular) or state (solid, liquid, or gas)
• most are easily reversible
Examples of Physical Changes:
• Changes of state (boiling, melting, freezing, condensation, sublimation)
• Dissolving (ex. Dissolving sugar in water - the sugar particles spread out, but they are still there, as sugar particles.)
Chemical Changes
• always produce a new substance which has different properties from the starting substance(s)
• involve more than one substance
• many are not reversible
Examples of Chemical Changes:
• Burning paper (the gases and black substance formed are new substances, and cannot be reversed back to paper)
• Rusting nails (rust formed is a new substance, formed from the metal and oxygen)
How can we tell if a chemical change has occurred?Look for clues that a new substance has formed
Clues that indicate that a new substance has formed in a chemical reaction are;
• colour change (not a blending of the initial colours)
• gas (bubbles) is produced (not from boiling)
• a solid (precipitate) is formed when two solutions are mixed together
• energy is released (usually heat or light) or absorbed (substance feels colder), but not because of heating with a burner or cooling with ice etc.
• odour change / new odour
Physical or Chemical Change?
Chemical
Physical or Chemical Change?
Chemical
Physical or Chemical Change?
Physical
Physical or Chemical Change?
Chemical
Physical or Chemical Change?
Physical
Physical or Chemical Change?
Chemical