Redox Flashcards
What are the oxidation states of he following Ligand? H2O NH3 OH- Cl- CN- Cr2O72- H2NCH2CH2NH2 EDTA4-
0 0 -1 -1 -2 0 -4
Why can you add water in redox reactions to mop up oxygen?
What’s the equation for the reduction of VO3- to V2+?
They react with the hydrogen ions
VO3-+6H++3e- > V2++3H2O
Electrode potentials
What does the half equation represent?
What are all the half equations listed as in terms of redox?
Half reaction
Reduction
Electrochemical Cell What is this also known as? What do the electrodes act as? What are they immersed in? What does this act as? What is this usually? What do the electrodes and this together form? What does the salt bridge do? How does it do this? What is the salt bridge made of?
Fuel cell Electron conductor Electrolyte Ionic conductor Molten salt or aqueous solution Electrode compartment Completes the circuit Allows ions to move while keeping compartments separate Filter paper soaked in saturated KCl or KNO3
Electrode Reactions
What does each electrode compartment support its own?
What are electrons released by oxidation in one compartment made available for?
How do they get to this?
Half reaction
Reduction in other compartment
Following external wire
Working out cell equation
What is the right hand in terms of redox?
What is the left hand in terms of redox?
What do you do when you have these both?
Reduction
Oxidation
Add them together
Cell potential
What is potential difference set up between?
Which electrode is more negative?
What is each electrode also known as?
What does each electrode have its own? And what is this also known as?
When is it altered by?
The 2 electrodes Left Half cell Electrode potential half cell potential Concentration temperature pressure
Standard Electromotive Force (emf)
What are the standard conditions?
What is the definition for emf?
1Molar,298K,100kPa,zero current
Potential difference in volts between electrodes of a standard electrochemical cell measures under zero current conditions
Standard Hydrogen Electrode (SHE)
Can’t work out half cell on own but can work out difference between 2
What is one electrode assigned the value of?
All electrodes are measured relative to this
What is the value of the standard electrode potential?
Draw a diagram of this
What’s the hydrogen reduction half equation?
What type of electrode is this?
0
0v
2H+(aq)+2e- > H2(g)
Test tube with pt inside immersed in solution of h+
H2 added through test tube and salt bridge
Gas electrode
What is the definition of the standard electrode potential of a half cell/electrode?
Potential difference that exists between it and a standard hydrogen half cell under standard conditions
What are the three different types of half cell?
Metal electrode
Gas electrode
Redox electrode
Metal electrode
What is it?
Draw example
what does M2+/M represent?
Metal in equilibrium with solution of its ions
Redox couple
Gas Electrode
What is it?
What is the inert metal usually?
What does the inert metal act as? What does it provide?
Inert metal surrounded by gas in equilibrium with its ions
Pt
Source/sink for electrons
Surface for electron transfer
Redox Electrode
What is it?
Draw an example
Inert metal immersed in solution with 2 different oxidation states of given element
Cell diagrams and equations
What does || represent?
What does | represent?
Which side is the more negative on?
Therefore in terms of redox which is on the left?
Red|Ox|Ox|Red
Draw out for oxidation of zinc with reduction of copper
Draw out for oxidation of Fe2+ to Fe3+ with reduction of MnO4- to Mn2+ with H+ ions
Salt bridge Phase boundary Left Oxidation Zn(s)|Zn2+(aq)||Cu2+(aq)|Cu(s) Pt(s)|Fe2+(aq),Fe3+(aq)||MnO4-(aq),Mn2+(aq),H+(aq)|Pt(s)
