Redox Flashcards
(28 cards)
What is the oxidation of Calcium? (1)
Ca → Ca²⁺ + 2e⁻ (1)
What is the reduction of Oxygen? (1)
1/2O2 + 2e- → O2- (1)
What is the oxidation numbers of Aluminum and Fluorine? (2)
- Al = +3 (1)
- F = -1 (1)
What is a disproportionation reaction? (1)
- Where a species is being
simultaneously oxidised and
reduced (1)
How do you balance equations? (5)
- Write the species before and
after a reaction (1) - Balance atoms except for
oxygen and hydrogen (1) - Balance oxygens with H2O (1)
- Balance hydrogens with H+ (1)
- Balance charges with e- (1)
How do you combine half equations? (2)
- Balance and cancel the
electrons (1) - Combine the 2 equations (1)
What is an electrochemical cell? (1)
- A device that generates
electrical energy from chemical
reactions (1)
How do you set up an electrochemical cell? (5)
- Remove metal surface
impurities with sandpaper (1) - Remove grease with
propanone (1) - Place each metal in a solution
containing the ion of their
metal (1) - Make a salt bridge with filter
paper soaked in saturated KNO3 (1) - Connect electrodes with wires
and voltmeter (1)
When is a platinum electrode used and why? (2)
- When there is a half cell with 2
aqueous ions (1) - It is inert but electrically
conductive (1)
How do electrons flow in electrochemical cells? (2)
- From a more reactive metal to a less (1)
- The one being oxidised to the one being reduced (1)
What observations are made during electrochemical cell? (2)
- Metals being oxidised will result in a thinner electrode as more Zn2+ is produced (1)
- Metals being reduced will result in a thicker electrode as Cu2+ receive electrons to turn into Cu (1)
What is the electrode potential? (1)
- Tells us how easily the half cell gives up electrons/oxidised (1)
How do we work out what half cell is being oxidised? (3)
- Write the 2 half cell equations in reduced form: Zn2+ + 2e- -> Zn
- The most negative half cell from the data book will undergo oxidation (1)
- The equation is flipped (1)
How are standard electrode potentials measured? (3)
- Against a reference standard hydrogen electrode (1)
- Which consists of a platinum electrode with H+ ions (1)
- At standard conditions to give an electrode potential of 0.0V (1)
What is the trend of reducing and oxidising power in the electrochemical series? (2)
- Products become stronger reducing agents down the series (1)
- Reactants become stronger oxidising agents up the series (1)
What is the standard cell potential calculation? (1)
E0 = Ereduced - Eoxidised (1)
Why do we use standard electrode potentials? (2)
- Not having standard conditions will affect equilibrium position (1)
- Which affects cell potential value (1)
How do we write cell notation of an electrochemical cell? (2)
Reduced form | Oxidised form || Oxidised form | Reduced form
- The more negative E0 is on the
left side (1)
What is the cell notation of a half cell with 2 aqueous ions (2)
- Fe3+(aq), Fe2+(aq)| Pt(s)
- Comma represents ions being
in the same physical state (1)
What do lines represent in cell notation? (2)
- Single solid line shows physical
state change (1) - Double solid line shows salt
bridge (1)
How do you work out reaction feasibility? (3)
- Most negative standard
electrode potential is oxidised
(1) - E0 = Ereduced - Eoxidised (1)
- Positive E0 value is feasible (1)
How is entropy, cell potential and equilibrium constant linked? (1)
- They are all directly
proportional to each other (1)
How do rechargeable batteries work in electrochemical cells? (3)
- Plugged in to supply a current
(1) - Forces electrons to flow in the
opposite direction (1) - Reverses the overall discharge
equation (1)
How do fuel cells differ from batteries in terms of electricity production? (2)
- Electricity in fuel cells is
generated by a continuous
external supply of chemicals (1) - Batteries have a ‘ready store’ of
chemicals (1)
