cells and batteries

• electrochemical cell

  is a basic system made up of two different electrodes in contact with an electrolyte

  
• what are the electrodes made of?

  metals - as they should be able to conduct electricity
• what factors affect the voltage?

  the difference in reactivity between the electrodes

  the electrolyte

  if it is a cell or a battery
• electrode reactivity

  the larger the difference between the reactivity between the electrodes the bigger the voltage of the cell
• the electrolyte used in the cell

  different ions in the solution will react differently with the metal electrodes used
• battery

  battery is two or more cells connected together in series

  the voltages of the cells in the battery is combined so there is a bigger voltage overall
• non-rechargeable battery

  over some time the reacting particles - the ions in the electrolyte and the metal ions on the electrodes get used up and turn into products of the reaction
• what happens when one of the reactants is used up?

  the reaction cant happen and no electricity is produced
• example of non rechargeable battery

  alkaline batteries - once one of the reactants is used up, the don't produce any more charge and you have to replace them
• rechargeable battery

  the reaction can be reversed by connecting it to an external electrical current