9Fa

• Physical change is something that changes the physical properties of a substance - like size shape or form
• Chemical reaction is a reaction that rearranges particles of two or more substances to create at least one new substance
• During a chemical change

  • changes can not be undone - not reversible
  • New substances are created during a chemical change
• During a physical change

  • they are easy to reverse
  • no new substances are created
• evidence for chemical change - Bubbles, A colour change giving off light/heat, producing an odour, releasing gas, creating sound
• evidence for physical change - melting, boiling and dissolving
• Gas pressure is the force exerted by gas particles colliding with the wall of their container
• Pressure is defined as force exerted over an area
• Gas pressure is the force exerted by a gas on a specific area
• Pressure can be increased by:

  • Increasing the number of particles
  • Reducing the size of the container
  • Increasing the temperature