Physical and Chemical Changes

1
Physical and Chemical Changes

• Phases of Matter and
• Phase Changes

2
Physical Property

• Characteristic that distinguishes one type of
  matter (wood) from another type (water)
• Can be observed without changing the identity of
  the substance
• Examples mass, weight, volume, density, color,
  shape, hardness, texture, phase of matter

3
Solids

• Definite shape
• Definite volume
• Particles packed tightly together
• Little to no movement, vibration
• Crystalline solid regular, repeating pattern
  snowflakes, diamonds
• Amorphous solid lose their shape under certain
  conditions wax, glass, tar

4
Liquids

• No definite shape
• Definite volume
• particles not held as tightly together as solids
• Free to move, flowing
• Viscosity resistance to flow
• Honey has a high viscosity
• Water has a low viscosity

5
Gases

• No definite shape
• No definite volume
• Particles fill all the available space
• Particles move freely
• Boyles Law
• Increase pressure, decrease volume
• Charles Law
• Increase temperature, increase volume

6
Plasma

• Rare on Earth
• Most common in Universe STARS
• Extremely high in energy

7
Phase Changes Physical Changes

• What causes matter to be in one phase or another?
  ENERGY!
• Adding energy (heat) causes particles to move
  faster and further apart
• Taking away energy (heat) causes particle to move
  slower and closer together
• Sosolids (ice) has less energy than liquids
  (water). Gases (steam) have even more energy.
  Plasma has the most.

8
Phase Changes

• Melting solid to liquid (add energy)
• Freezing liquid to solid (take away energy)
• Vaporization liquid to gas (add energy)
• Evaporation takes place at the surface
• Boiling takes place at the surface AND inside
  the liquid
• Condensation gas to liquid (take away energy)
• Sublimation solid to gas (add energy)
• Dry ice, snow disappearing

9
Physical Changes

• A new substance is NOT formed
• Change in color, size, shape, phase of matter,
  etc.
• Cutting paper
• Freezing water
• Melting butter
• Squeezing lemons
• Mixing Kool-aid powder with water

10
Chemical Properties

• Describes how a substance COULD change into a new
  substance
• Flammability ABILITY to burn
• Ability to rust
• Ability to tarnish

11
Chemical Change

• The process by which the substance actually
  changes into a new and different substance
• Another name for chemical change is chemical
  reaction
• Burning
• Rusting
• Tarnishing
• Leaves changing color
• Fireworks
• Baking a cake