Chemical and physical change

• Mixture


  A combination of two or more substances that are not chemically bonded together
• Separation techniques


  • Paper chromatography
  • Different experimental techniques
• Chemical change


  When atoms rearrange themselves to form new chemicals
• Physical change


  When a substance changes without becoming a new chemical
• Differences between physical and chemical change


  • No new substances formed (physical)
  • New substances (products) formed (chemical)
  • Usually easy to reverse (physical)
  • Usually difficult to reverse (chemical)
  • Usually no significant energy change (physical)
  • Energy given out (exothermic) or taken in (endothermic) (chemical)
  • Usually no colour change (physical)
  • Can result in colour change (chemical)
  • Substance usually changes state (physical)
  • New products can have different state (chemical)
• Changes in energy


  • Warming or cooling
  • Release of light
• Mass is never lost or gained in chemical reactions. It is said that mass is always conserved.
• The total mass of products at the end of the reaction is equal to the total mass of the reactants at the beginning.
• No atoms are created or destroyed during chemical reactions.