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