1. Three ways that explains that fuel cells are better than primary and secondary cells are listed below:
• There are no toxic reactants
• There are no waste products as water is the only product
• They are very efficient energy converters (70-80% efficient)
2. The overall balanced chemical equation for the button cell is:
HgO9(s) + Zn(s) ( Hg(l) + ZnO(s)
3. Primary cells can generate a larger maximum voltage than secondary cells. This is not a problem when it comes to operating electronic devices that require more voltage because by making a series of cells, primary cells will generate more voltage than secondary cells do, while using the same number of cells.
4. A cell can no longer supply energy when it cannot provide a closed path for electrons and ions to travel. A cell can fail when:
• The reactants are all used up in a dry cell.
• Rechargeable batteries are not drained completely before recharging
• The steady flow of reactants is removed from a fuel cell.
5. Fuel cells are not used on a large scale basis because they are very expensive and they require a continuous supply of reactants and constant removal of products.
6. Alkaline batteries are dangerous when dissected because they may come back to life from the electrical charge of so many batteries and they are also very dangerous for our environment. Therefore, batteries packages often carry a warning label to tell the customer to not dissect alkaline batteries.
7. Ag2O would most like generate a higher voltage than HgO because Ag2O is more reduced and thus it is more likely to generate a high voltage.
8. In dry cells, graphite (or some other inert electrode) is used as the cathode because graphite serves as a solid support for the reduction half-reaction.