Chemical Analysis

• What is a pure substance?

  A substance containing a single element or compound
• What is an impure substance?

  A substance containing more then one type of element or compound (mixture)
• What are examples of formulations?

  • Fuels
  • Paints
  • Foods
• What is a formulation?

  A mixture with a specific purpose
• What are the methods for separating mixtures?

  • Filtration
  • Crystallisation
  • Simple distillation
  • Fractional distillation
• How do you calculate the Rf value?

  Distance moved by substance ÷ distance moved by solvent
• What is the mobile phase?

  The solvent
• What is the stationary phase?

  The paper
• How do you test for hydrogen?

  • Hold a lit splint near the gas
  • Squeaky pop
• How do you test for oxygen?

  • Hold a glowing splint by the gas
  • Splint re-lights
• How do you test for carbon dioxide?

  • Bubble the gas through limewater
  • Limewater turns milky
• How do you test for chlorine?

  • Hold damp litmus near the gas
  • Bleaches litmus white