OCR A-Level Chemistry: Chapter 23 - Redox And Electrode Potentials
This flashcard set defines redox, oxidation, and reduction, and includes key half-equations for manganate and iodine-thiosulphate reactions. It also explains the visual challenge in detecting the endpoint of vanadium and potassium manganate titrations due to similar solution colors.
Define redox
A reaction in which both reduction and oxidation take place.
Key Terms
Define redox
A reaction in which both reduction and oxidation take place.
Define oxidation
The loss of electrons or an increase in oxidation number.
Define reduction
The gain of electrons or a decrease in oxidation number.
What is the Manganate half reaction?
MnO(4)- + 8H+ + 5e- -> Mn2+ + 4H(2)O
What is the iodine sodium thiosulphate reaction?
2S(2)O(3)2- + I(2) -> S(4)O(6)2- + 2I-
Why is there no clear colour change at the end point of a Vanadium and Potassium Manganate titration?
KMnO(4) is purple/pink
V2+ is violet
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Define redox | A reaction in which both reduction and oxidation take place. |
Define oxidation |
|
Define reduction | The gain of electrons or a decrease in oxidation number. |
What is the Manganate half reaction? | MnO(4)- + 8H+ + 5e- -> Mn2+ + 4H(2)O |
What is the iodine sodium thiosulphate reaction? | 2S(2)O(3)2- + I(2) -> S(4)O(6)2- + 2I- |
Why is there no clear colour change at the end point of a Vanadium and Potassium Manganate titration? | KMnO(4) is purple/pink V2+ is violet |
What property does the voltmeter have in a cell? | High resistance |
Which way does the current flow in the cell? | Negative electrode to the positive electrode |
How do the ions flow between cells? | Salt bridge |
What is the salt bridge generally made of? | Potassium nitrate Ammonium nitrate |
What is the electrode made of in a standard hydrogen cell? | Platinum |
What is in the half cell of Fe3+ and Fe2+? | Inert Pt electrode Equimolar Fe2+ and Fe3+ (1 mol dm^-3) |
When two half cells are connected, which is oxidised and which is reduced? | More reactive metal is oxidised Less reactive metal is reduced |
Define standard electrode potential | The emf of a half cell compared with a standard hydrogen half cell, measured at 298K with solution concentrations of 1 mol/dm^3 and a gas pressure of 101kPa. |
What is the electrode potential of a hydrogen half cell? | 0.00V |
What is the electrode potential of the cell? | Electrode potential of the positive terminal minus the electrode potential of the negative terminal |
How do we know if a cell is feasible? | If the electrode potential of the cell is positive, the reaction is feasible. |