From past paper

• What element is stored under oil?

  Na (sodium)
• What element is found in the ore zinc blende?

  S (sulfur)
• Which element forms an oxide which is the main imuprity in iron ore?

  Si (Silicon)
• Name two substances which react with water to form calcium hydroxide?

  Calcium oxide and calcium carbide.
• How would you test for the presence of calcium ions in a sample of limewater?

  Test: Sodium hydroxide - white precipitate forms which is insoluble in excess
• Give two chemical properties of the trasnition metals

  Can act as catalysts, and have variable oxidation states.
• Fluroine and chlorine are halogen - suggest the appearance of fluorine?Yellow - gas.
• Ethanol is oxidised by heating it with dilute sulfuric acid and what other reagent?

  Potassium manganate (VII).
• What chemical process is used to break polymers into monomers?

  Cracking
• Describe the test for water using cobalt chloride

  Blue cobalt (II) chloride turns pink in water.
• Describe the test for copper (II) sulfate in water?

  White anhydrouous copper (II) sulfate turns blue in water.
• How are nitrogen and oxygen seperated from clean dry air?

  Fractional distillation - Oxygen has a higher boiling point than nitrogen Both are turned into liquid air, and then the fractioning columns temperature increases until nitrogen boils (at around 196) and it is then condensed and collected - temperature then increases again until oxygen boils and the same occurs.
• How can a carbohydrate polymer be broken down into a simpler sugar?

  Hydrolysis
• What is hydrolosis?


  Hydrolosis is the splitting of up of a molecule using water (often used in organic chemistry).