Cells Flashcards
How to produce electricity
Take two different metals and place them into an electrolyte
Describe an electrolyte
A solution that can conduct electricity
Disadvantage of a cell
- Can only produce electricity for a certain period of time
= eventually chemicals in cell run out and reaction stops - Cells only produce electricity if we use metals with different reactivities
Describe potential difference of a cell
The greater the difference between the reactivity of the metals the greater the potential different produced by the cell
Describe a battery
Contains two or more cells connected in a series to produce a greater voltage
How do we recharge batteries
Reverse chemical reactions when we apply electrical current
What happens in a fuel cell
React hydrogen with oxygen
Negative electrode half equation of a fuel cell
2H2 = 4H + 4e-
Positive electrode half equation of a fuel cell
O2 + 4H + 4e- = 2H2O
Overall equation of a fuel cell
2H2 + O2 = 2H2O
Hydrogen is being oxidised
Adv of hydrogen fuel cells
- take less time to refuel
- travel further without refuelling
- don’t get less efficient the longer get they run
- can be a source of drinking water
- water is only product no carbon emissions
Disadvantages of rechargeable batteries
- they run out and must be recharged
- can store less electricity the more charging cycles they go through
Disadvantages of hydrogen fuel cells
- run on hydrogen which is an explosive gas and difficult to store safely
- produce a low potential difference
- production of hydrogen uses fossil fuels
- not sold everywhere
Advantages of rechargeable batteries
- no dangerous fuels are required
- can produce a greater potential difference than a hydrogen fuel cell
- reversible reaction
= pass electricity through battery causing reaction to go in reverse direction
= recharging the reactants
