Chemical Changes

    Cards (33)

    • What is Oxidation?
      Substance gains oxygen
    • What is reduction?
      Substance loses oxygen
    • When reacted with water :
      What do Group 1 metals make ?
      Metal hydroxide + Hydrogen
    • What elements have no reaction with water?
      Magnesium , Zinc , Iron & Copper
    • What do you have to react the Group 1 elements that do not react with water with instead?
      Dilute acid
    • O xidation
      I s
      L ost
      R eduction
      I s
      G ained
    • How do you extract Unreactive metals?
      Found in earths surface
    • How can metals which are less reactive than Carbon be extracted ?
      By reduction of Carbon
    • Acid + metal ---> Salt + Hydrogen
    • Are acids H+ or OH- ?
      H+
    • What is neutralisation?
      Acids being neutralised by alkali and bases .
    • Acid + Metal oxide ---> Salt + Water
    • Acid + Metal carbonate ---> Salt + Water + CO2
    • How are soluable salts made?
      Made from acids by reacting them with solid insoluable substances
    • OH- in terms of pH scale :
      Alkaline
    • H+ in terms of pH scale :
      Acid
    • What are Titrations used for ?
      Used to measure volumes of acid & alkali solutions that react with eachother
    • What is a strong acid in terms of Ionisation?
      Completely Ionised
    • Examples of Strong Acids :
      • Hydrochloric
      • Nitric
      • Sulfuric
    • What is a weak acid in terms of Ionisation?
      Partially ionised
    • Examples of Weak Acids :
      • Ethanoic
      • Citric
    • The stronger acid , the lower the pH .
    • As pH scale decreases by 1 unit, Conc of H+ ions increases by 10x
    • What is Electrolysis?
      Use of electronic current to break down compounds containing ions into consistuent elements
    • What is the Electrolyte?
      Substance used to break down, able to conduct electricity
    • + Ions move to cathode
    • -- ions move to Anode
    • Why is Electrolysis expensive?
      • Melting compounds requires a lot of energy
      • Lots of energy required to produce electrical current
    • Metal produced at Cathode
    • Non-metals produced at Anode
    • Electrolysis in Aqueous solutions :
      + electrode = Hydrogen produced if more reactive than hydrogen
      -- electrode = oxygen produced unless solution contains halide ions
    • Why at - electron is oxygen produced unless solution contains halide ions?
      H2O molecules break down producing H ions and hydroxide ions are discharged.
    • What does Cryolite do?
      Lowers melting point