Electrochemical cells made simple

Question 1

what are batteries

Answer 1

tpye of electrchemical cells

Question 2

What are the advtage and disadvatnage of rechargable batteries in term of cost

Answer 2

• disadv
  
  • higher intiial cost
• adv
  
  • last longer
  • work out cheaper in the long run

Question 3

What are the features of a lithium cell

Answer 3

• made up of lithium cobalt oxide electrode
• graphite electrode
• the electrolyte is a lithium salt in an organic solvent

Question 4

What are the ha;f eqiatopm in the lithium cell?

Answer 4

• ​-ve electrode
  
  • Li → Li⁺ + e^-
  • more -ve E^o value
• +ve electrode
  
  • Li⁺ + CoO₂ + e^- → Li⁺[CoO2]^-

Question 5

How is the lithium cell recharge

Answer 5

• current supplied to force electron to flow in the opposite direction around the circuit and reverse the reactions

Question 6

How is a fuel cells different?

Answer 6

• chemical s stored seperately outside the cell and fed in when electricity is needed

Question 7

What is the use of the alkaline hydrogen-oxygen fuel cell?

Answer 7

power vehicles

Question 8

How does the alkaline hydrogen-oxygen fuel cell work?

Answer 8

• hydrogen and oxygen gases are fed into two seperate platinum-containing electrode
• the electrode are se[erated by an anion-exchange membrane, that allows anions (hydroxide) and water to pass through it but not hydrogen and oxygen gas
• the electroylte is aqueous KOH soln

Question 9

What are the reactions that occur?> What happens in terms of electrons/anion transfer

Answer 9

Question 10

What are the advtangages of using fuel cells in car?

Answer 10

• more efficient
  
  • convert more of their available energy to KE of the moving car
• the only waste product is water, no toxic chemicals to dispose of and no CO2
• fuel cells don’t need to be recharged like batteries, as long as hydrogen and xoygen are supplies the cell will continue to produce electricity

Question 11

What are the down side of the fuel cell

Answer 11

• need energy to produce a supply of hydrogen and oxygen
  
  • can be from electrolysis of water, reusing waste product
• requires electricty, usually acquired by burning fossil fuels
• hydrogen is highly flammible and needs to be handled carefully when stored or transports