Chemical And Fuel Cells Flashcards
(14 cards)
How to make simple chemical cell
Connecting two different electrodes and putting them in a liquid electrolyte
How do chemical cells produce electricity
The difference in reactivity of the 2 electrodes produces a voltage ( electricity)
Hydrogen fuel cell equation
2H² + O² —- 2H²O
How to change voltage output of a chemical cell to make the voltage output bigger
Changing the type of electrodes so there’s a greater difference in reactivity between the 2, resulting in a greater voltage
Change the type if electrolyte to one which reacts with the electrodes to form a greater voltage output
What is a battery
Collection of more than one cell joined end to end
Voltage of battery =
Sum of voltage of all the cells in the battery
Why are some batteries rechargeable
They are connected to an electric currant which reverses the reaction at the electrodes
Why are some batteries non rechargeable
Irreversible reactions take place at the electrode
How do fuel cells produce electricity
Reaction between fuel source ( usually hydrogen) and oxygen.
The fuel is added to the cell which has a constant supply of oxygen.
The fuel is fully oxidised creating a voltage
Advantages of fuel cells
High efficiency
Less pollution
Lightweight
Reliable
Waste product of hydrogen fuel cell
Water
How does hydrogen fuel cell work
Hydrogen pumped in at anode
Hydrogen ions are formed as the Hydrogen is oxidised( looses electrons)
Oxygen is pumped in at the cathode
Water forms as the O² and H plus ions bond
Hydrogen fuel cells vs battery
Battery’s are made from toxic metals and cause pollution when diposed vs HFC only waste product is water and are made of natural gasses oxygen and hydrogen
Battery’s must be replaced vs HFC don’t need replacing
HFC produce more energy and batteries have a smaller capacity
Disadvantages of HFC
Have to be stored at high pressure
Hydrogen gass is explosive
