C7.5 - Chemical Cells And Batteries (Finished) Flashcards
How is an electrochemical cell structured?
Two different electrodes in contact with an electrolyte
What is the electrolyte?
A liquid that contains ions which react with the electrodes
What are the two electrodes in an electrochemical cell usually and why?
Metals as they have to be able to conduct electricity
How do electrochemical cells work?
1) the electrolyte reacts with the electrodes
2) These chemical reactions set up a charge difference between electrolyte and electrodes
3) If electrodes are connected by wire a charge can flow and electricity is produced
(Electrons will flow through the wire from one electrode to another)
Give 3 factors that can affect the voltage of a cell
- type of electrode
- difference in reactivity between electrodes
- electrolyte used
Why do different types of electrode affect the voltage of a cell?
Different metals will react differently with the same electrode so the charge difference will be different
The ___ the difference in ___ between the electrodes, the bigger the ___ of the cell.
Bigger, difference, voltage
Why will the type of electrolyte used affect the voltage of a cell?
Different ions react differently with the electrodes used
How is a battery formed?
A battery is formed by connecting two or more cells in series
How do rechargeable batteries work?
The battery is connected to a power supply that reverses the reactions that occur at each electrode when the cell is discharging, regenerating the original reactants
Why do batteries run out of charge?
Over time the reactants get used up, when one is used up, the reaction can’t happen
Which way do electrons flow in electrochemical cells and why?
There is a tendancy for metal atoms to give away electrons and form a positive ion, the greater the tendency the greater the reactivity so electrons flow from more reactive to less reactive
