Vocabulary
Define reducing agent/reductant.
A chemical species that causes another species to undergo reduction. Itself, undergoes oxidation by donating one or more electron.
Write the overall equation of Cobalt metal reacting with Silver ions.
2Ag+(aq) + Co(s) --> 2Ag(s) + Co2+ (aq)
What functions similarly to the salt bridge in galvanic cells used in fuel cells?
The electrolyte
When is Miss Lee going to get married?
January 2025
What is an oxidation number? Why do we use it?
A number assigned to an atom that can be used to find if there is electron transfer in a redox reaction.
Write a thermochemical equation for the combustion of ethane gas.
2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(l)
ΔH: -3120 kJ/mol
State the difference of electrodes used in galvanic cells and fuel cells.
Fuel cell uses porous electrodes but not in galvanic cells.
What 2 instruments can Ms Lee play?
Piano and violin
What is an electrolyte in primary/fuel cells? List one function of it.
A solution or liquid or gel that contains ions. Used to balance ion charges of the cell.
Calculate the amount of energy released when 3.60kg of butane is burnt in an unlimited supply of oxygen.
n=m/M = 3600g/58 = 62.1mol
Energy= n x Heat of combustion = 62.1 x 2880 = 178848 = 1.79 x 105KJ
Compare the energy efficiencies in an AA battery compared to the Hydrogen-Oygen fuel cell.
AA battery: 60-90% efficient
Fuel cells: 40-60% efficient but if use the waste heat energy to continue making electricity, increases to 80-90% efficient.
How many years has Miss Lee been teaching Chemistry? (Including your year)
6 years
What is the difference between Standard Electrode Potential (E°) and Standard Hydrogen Electrode (SHE)?
E° is the potential voltage of a half-cell measured in Volts.
SHE is the STANDARD half-cell of 0.00V where other elements are compared to and how the electrochemical series is created.
Write the anode and cathode reactions that happen in an alkaline fuel cell.
Cathode: O2(g) + 2H2O(l) + 4e- --> 4OH-(aq)
Anode: H2(g) + 2OH-(aq) --> 2H2O(l) +2e-
State 2 advantages and 2 disadvantages using fuel cells in a commercial car.
ADV: lower emissions of greenhouse gases/ more quiet/ greater efficiency than direct combustion / low maintenance and running costs
DISADV: storage and safety issues with highly reactive Hydrogrogen gas/ expensive to make porous electrodes/ Not as efficient
What is Miss Lee's favourite colour and list 2 pets she had in the past.
Lilac / Purple
Fish/ turtle / hamster
Define "SUSTAINABLE".
Substances that can be produced at a rate greater or equal to the rate of consumption without comprising future generations.
What volume of Hydrogen gas is produced under an acidic environment when a current of 15A for 1 hour is carried out under SLC?
Q = I x t = 15 x 60 x 60 = 54000 C
n(e-) = Q/F = 54000/96500 = 0.5596 mol
n(H2) = required/given =1/2 x 0.5596 = 0.2798 mol
V(H2) = n x Vm = 0.2798 x 24.8 = 6.9 L
List 3 points and explain how are fuel cells designed to maximise energy efficiency in the industrial world.
1. Using a catalyst
2. Using porous electrodes
3. Hybrid systems
4. Cogeneration
5. Operating conditions
6. Durability
7. PEM electrolytes
List 5 items Miss Lee only carries in her pencil case.
1. White board marker
2. Pen
3. Scissor
4. Ruler
5. Bull dog clip
6. Sharpie