Cells Flashcards
What does a high e cell value mean
It’s a good oxidising agent and is easily reduced
Why might a reaction not take place if the e cell value is positive
Rate of reaction so slow that reaction doesn’t appear to happen
It has a high activation energy
What are fuel cells
Generate electricity from reacting a fuel with an oxide
What happens are the anode in a fuel cell
Platinum catalyst splits H2 into protons and electrons
What happens in The polymer electrolyte membrane of a fuel cell
It only allows the H+ across forcing the e- to travel around the circuit to get the cathode
What happens at the cathode of a fuel cell
O2 combines with the H+ from the anode and the electron from the circuit to make H2O water is the waste product
À davantage of electrochemical cell
They are more efficient at producing energy than combustion engines. Less energy wasted as hear
Produce less pollution. Hydrogen fuel cells the only wafer product is water
Disadvantage of electrochemical cells
Making the cells need toxic chemicals to which need to be dispersed of once the cell has reached the end of its life span
The same chemicals are very flammable(lithium) highly reactive and will catch fire if a fault causes it to overhewt
are primary cells rechargeable
no. They are designed to be used once. Chemicals are sued up and voltage falls battery goes flat
were are primary cells found
wall clocks and smoke detectors
what are most modern primary cells based on
Zn and MnO2
Zn+2MnO2=ZnO + Mn2O3
what makes secondary cells rechargeable
the reaction can be reversed during recharging, the chemicals are regenerated and the cell can be used again
examples of secondary cells
lead-acid batteries used in car
nickel-cadmium use nickel metal hydride used in radios torches
lithium ion cells used in laptops tablets camera phones
