Electrochemical and Electrolytic Cells Flashcards
What is the purpose of the electrolyte?
Allows for only movement of ions between electrodes. Maintain charge neutrality.
What is a Fuel Cell
A fuel cell is a type of galvanic cell which converts chemical energy to electrical energy using a continuous supply of reactants.
What is a Direct Reaction
Chemical energy being converted to Heat Energy
What is an Indirect reaction
Chemical energy being converted to electrical energy
What if there is a SMALL difference in electric potential within a Galvanic Cell
Other reactions may occur. e.g. ‘whiff of chlorine’
Why do Fuel Cells use POROUS electrodes
Porous electrodes allow for gas to access electrolyte and it has a large SURFACE AREA
What are advantages of Fuel Cells
High Energy Conversion efficiency
Low running costs
Low chemical pollution
What are disadvantages of Fuel Cells
Initial cost is expensive
Continuous supply of fuel
H2 gas is difficult to store
List KEY differences between Galvanic and Fuel Cells
Galvanic - carbon electrodes, separate vessel, requires continuous supply
Fuel cell - porous electrodes, same vessel, contains products and reactants
Why is a fuel cell considered renewable
H2 that is produced do not require large land to produce. No release of CO2
What are the 2 types of Electrohemical Cells
Primary and Secondary
Outline the difference between Primary and Secondary Cells
Primary: Non-rechargable, uses porous separators
Secondary: Rechargable, no need for separator as reaction is non-spotaneous
What are the conditions for a secondary cell to be rechargeable
Products of discharge reaction must stay at electrodes
Outline the 2 reactions in a secondary cell
Discharge - chemical –> electrical
Recharge - electrical –> chemical
What affects Battery life of secondary cells
High temp –> decreases battery life
Low temp –> decreases ROR –> decrease energy
Corrosion
Products do NOT stay at electrodes
