All substances have properties… Including people! Example: People can be identified by their …...
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Transcript of All substances have properties… Including people! Example: People can be identified by their …...
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
Physical Properties
Physical properties are physical characteristics that identify the element based on its nature such as:
Melting point: the temperature at which the solid changes to liquid
State at room temperature: solid, liquid or gas
Density: the mass per volume
Luster: the ability to reflect light in a metallic shine
Boiling point: the temperature at which the liquid changes to a gas
Viscosity: the ease with which a substance flows.
This is a descriptor of liquids. Water flows more easily and is therefore, more viscous, than honey.
Colour
Clarity or Transparency: the amount of light that can pass through a substance.
Opaque: when no light passes through Translucent: when some light passes throughTransparent: when all light passes through
Malleability: the ability to be hammered into thin sheets
Ductility: the ability to be drawn into wire
Conductivity: the ability to conduct heat or electricity
Solubility: the ability to dissolve in water.
Physical Properties can be classified as Quantitative or Qualitative:
Qualitative properties describe matter using words. They cannot be measured or expressed numerically (no numbers involved).
Quantitative properties can be measured and expressed numerically (numbers are involved)
Qualitative Quantitativephysical state melting pointcolour boiling pointodour densitycrystal shape solubilitymalleability ductility hardness brittleness texture
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
Reactivitywith acids
Physical and Chemical ChangesPHYSICAL CHANGES:• do not produce a new substance (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…• Cutting• Tearing• Grinding
• Change in State• Dissolving• Molding (shaping)
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• rusting• eating (saliva action on food)
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