Comparison of a Button Cell to a Dry Cell By Elisha, Jeremy and Tom Button Cell Chemistry of the Button Cell • Half Equations ▫ Cathode reaction Ag2O (s) + H2O (l) + 2e- → 2Ag (s) + 2OH▫ Anode Reaction Zn (s) + 2OH- → ZnO (s) + H2O + 2e- • Full Equation Zn (s) + Ag2O (s) → 2Ag (s) + ZnO (s) Cost and Practicality • • • • • Silver is an expensive metal The production of the cell is therefore expensive Non rechargeable Small and light Has a relatively long life span Impact on Society • Due to its small size it has allowed the production of small electrical appliances • Due to its non toxic nature it has allowed for it to be used inside the body Environmental Impacts • Due to its unrechargeable nature, it has to be discarded or recycled after only one use • Potassium hydroxide that is found within the cell is caustic (causing corrosion) • No highly toxic materials that will harm the environment Dry Cell/ Alkaline Cell Chemistry • Half Equations - ▫ Cathode reaction▫ MnO2(s) + 2H20(l) +2e Mn(OH)2 (s)+2OH (aq) ▫ Anode Reaction Zn(s)+2OH (aq) Zn (OH)2 (s) + 2e ▫ Overall Reaction ▫ MnO2(s) + 2H20(l) + Zn(s)+2OH(aq)Mn(OH)2 (s)+2OH (aq)+Zn (OH)2 (s) Cost and Practicality • Very cheap • Form of paste it is very convenient , being very transportable. • Small and easy to store and use • Maintains a steady voltage, therefore they are good for a range of electronic such as torches, walkman and toys. • Cannot be recharged • Short life • Cannot deliver a high current • Battery may leak Impact on Society • Due to its low constant voltage it is used for common appliances such as torches, toys and portable radios/cds • Due to its mobility , portable items like flashlights could be used , therefore increasing the development of electrial equipments/ devices. • The popularity of batteries have increased Environmental Impact • Small amounts of zinc are not problematic, however large amounts of zinc is a threat. • Manganese is also a heavy metal, dispose in large quantities are not beneficial for the environment.