Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
Electrode potentials
AQA A Level Chemistry
| Question | Answer |
|---|---|
| Write the balanced redox half equation for the oxidation of iron(ii) to iron(iii) | Fe2+ ——> Fe3+ + e¯ |
| "Write the balanced redox half equation for the MnO4¯ being reduced to Mn2+ in acidic solution | MnO4¯ + 5e¯ + 8H+ ———> Mn2+ + 4H2O |
| "Write the balanced redox half equation for Cr2O72- being reduced to Cr3+ in acidic solution | Cr2O72- + 6e¯ + 14H+ ——> 2Cr3+ + 7H2O |
| "Fill in the gaps in this phrase: Each electrode / electrolyte combination has its own half-reaction which sets up a ---------- ---------- because different cells have a different tendency to donate or accept ---------. | "Each electrode / electrolyte combination has its own half-reaction which sets up a potential difference because different cells have a different tendency to donate or accept electrons |
| On what variables does Electrode Potential depend? | "TEMPERATURE, PRESSURE OF ANY GASES, SOLUTION CONCENTRATION |
| Define Standard Electrode Potential | "The definition of standard electrode potential E° of a half cell is the voltage of that half cell relative to a standard hydrogen electrode when all solutions have a concentration of 1 moldm-3 all gases are at 1 atmosphere pressure and the temperature |
| What is the Standard Electrode Potential of a standard hydrogen half cell defined as? | 0.00V |
| What is the purpose of a salt bridge between two half cells? | it completes the circuit by allowing the transfer of ions. |
| How does one make a salt bridge? | Soak filter papers in a saturated solution of potassium nitrate. |
| By convention how are all half equations written for each standard electrode potential? | All equations are written as reduction processes |
| If two half equations are combined how do you know what the overall reaction will be? | "A species with a higher E° value oxidise (reverses) one with a lower value |
| Write an acronym to remember how to write a combination of cells in standard cell notation. | Reduced Oxidised Oxidised Reduced. ROOR |
| Write a formula to work out Ecell for a cell written in cell notation. | "Ecell= E°RHS-E°LHS |
| Write a formula to work out Ecell for a redox reaction. | "Ecell= E° half equation for the Reduction reaction - E° half equation for the oxidation half equation. |
| Write down the 7 rules for writing a cell in cell notation. | "ROOR, Add State Symbols, Species in the same state in the same half cell are separated by a comma, Species in different states are separated by a solid vertical line, If there is not solid species in the half cell you must add a Platinum Electrode, If th |
| Write the oxidation and reduction reactions occurring, and then write the overall reaction occurring in each cell for the Ag/Zn electrode pair. | "Zn(s) → Zn2+ (aq) + 2e- and Ag+(aq) + e- → Ag(s) so overall: Zn(s) + 2Ag+ (aq) → Zn2+ (aq) + 2Ag(s)" |
| Calculate the standard electrode potential of the Na+/Na electrode given that when it was joined to the standard hydrogen electrode, the cell emf was –2.71 volts. | -2.71 |
| Calculate the emf of a cell with the standard AgCl/Ag electrode (Eº = +0.22 V) as the left hand electrode and the Fe2+/Fe (Eº = –0.44 V) electrode as the right hand one. | emf = –0.44 – +0.22 = –0.66 V |
| Calculate Eºcell of the following cells using the Eº values from a data sheet: Ni2+/Ni Sn4+/Sn | 0.44 |
| Calculate Eºcell of the following cells using the Eº values from a data sheet: 2I-/I2, Ag+/Ag | 0.26 |
| "How can E° values be used to predict the feasibility of redox and cell reactions? | "In theory ANY REDOX REACTION WITH A POSITIVE ECELL VALUE WILL WORK, A half equation with a more positive E° value reverse a less positive one |
| Give two reasons why a redox reaction that is predicted to be feasible might not occur | Its activation energy might be too high, it might not be occurring under standard conditions. |
| How do the redox half equations that are set up in a rechargeable battery when the battery is being recharged compare to when it is being charged | They are reversed by an external current. |
| What are the pros and cons of non rechargeable batteries. | Pros cheap, small Cons waste issues due to very limited lifetime |
| What are the pros and cons of rechargeable batteries. | "pros: less waste, cheaper in long run, Cons time to recharge, still some waste issues because lifetime is still limited |
| " |
Created by:
JBearfield
Popular Chemistry sets