electrolysis

• why is electrolysis able to happen(ionic substances)

  when melted or dissolved ions are free to move about..
• How are solutions broken down into elements

  passing current though substances that are molten or solution
• what is the negative electrode called

  cathode
• what is the positive electrode called

  anode
• what is the negative ion called

  anion
• what is the positive ion called

  cation
• in lead bromide which element is produced at each electrode

  metal lead produced at cathode. non metal bromide produced at anode electrode
• why can't carbon be used to extract aluminium?

  aluminium more reactive than carbon. so carbon not able displace aluminium
• by what process is aluminium extracted

  electrolysis
• process of electrolysis aluminium

  large amounts of energy are used in extraction to melt compound and produce electrical current. aluminium manufactured by electrolysis with molten mixture of aluminium oxide and cryolite use carbon at positive electrode
• why is aluminium oxide mixed with cryolite

  aluminum oxide has very high melting point too expensive to melt
• why do the positive electrodes need to be continually melted

  oxygen is formed. carbon react with oxygen of the positive electrodes which form carbon dioxide. then gradually burn away
• what else can metals that are extracted with carbon be extracted by

  electrolysis
• what do the ions discharged in an aqueous solution depend on using inert electrodes

  relative reactivity of elements involved
• what is produced at negative electrode in aqueous solution and in what conditions

  hydrogen unless metal less reactive than hydrogen (more reactive ions want to stay within solution)
• what happens at positive electrode if oh- and halide ions are present

  one of halide ions produced.
• what happen s when no halide is present aqueous solutions

  oxygen formed
• why is oxygen formed in aqueous solutions when no halide is present

  water molecules break down which produces h+ ions and oh- that are discharged
• What is the pnemonic to help with describing oxidation and reduction in terms of electrons

  OILRIG
• In electrolysis in sodium chloride why is hydrogen produced at electrode

  sodium more reactive than hydrogen. so hydrogen produced
• definition of electrolysis

  electric current passed through substance to effect a chemical change
• what are solutions that conduct electricity called?

  electrolytes
• what are the cathode and anode made out of?

  graphite
• why is electrolysis very expensive aside high melting point needing lot od energy

  very expensive to produce electric current