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To design an electrochemical cell that produces an optimal energy output. …
To design an electrochemical cell that produces an optimal energy output.
How could energy output be measured
Voltemeter
Voltage (V)
Multimeter
A multimeter was chosen as the method of measuring the energy output as it measures multiple values such as Voltage and Current, which allows a range of possible experiments to be designed.
Initial planning for experiment
FINAL chosen dependant variable
Voltage measured using a Voltameter (V)
FINAL chosen independent variable
The depth of the electrodes submerged in electrolyte solutions
15cm
20cm
10cm
Factors to control
Surface area of electores
The electrodes used in the electrochemical cell (electromotive force difference )
Temperature
Electrolyte solutions
Volume of electrolyte solutions
Uncontrolled variables
Purity of electrodes
Room Temperature changes
Safety Considerations
Safety glasses
Gloves
Electrolytic Cell
Electric to chemical energy
Not spontaneous (requires energy)
Electrodes
Anode
Positive charge
Cathode
Negative charge
Applications
electroplating metals
recharging a battery
separating pure metals from metallic compounds
storing energy from renewable sources
Since the main problem or focus of this investigation is to effectively 'discharge', electrolytic cells would not be appropriate for this investigation
Galvanic Cell
Chemical to Electric Energy
Spontaneous (does not require energy)
Electrodes
Anode
Negative charge
Cathode
Positive charge
Applications
Fuel Cells
Electric Appliances
Discharging energy from renewable sources
This is part of the main injury question - so a galvanic cell would be appropriate in the experiment
Possible factors to change
Electromotive force
http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/electpot.html
Maximum potential difference between two electrodes of a cell
Calculated by using the Standard Electrode Potentials in Aqueous Solution at 25°C
Different electrodes parings to use
Zinc and Copper
Electromotive force = 0.76 + 0.16 = 1.1 V
Iron and Copper
Electromotive force = 0.41 + 0.16 = 0.57 V
Likely hypothesis/ expected trend
From research it is expected that the electrode pairing with the highest electromotive force would have the highest energy output
This is because higher EMF, means that there is a larger difference between the electrodes and thus a stronger attraction and electron flow
Aluminum and Copper
Electromotive force = 1.66 + 0.16 = 1.82 V
NOT chosen due to concerns of being too time consuming and possibility of material unavailable
Temperature
30
40
Room temperature
50
Likely hypothesis/ expected trend
NOT chosen
Length of electrodes submerged in electrolyte solutions
Possible lengths
https://opentextbc.ca/chemistry/chapter/17-7-electrolysis/
4cm
6cm
2cm
8cm
Likely hypothesis/ expected trend
It would be expected that the deeper the electrodes are submerged into the electrolyte solution the higher energy output.
This is due to more contact between metals, ions and electrons, eliciting a higher electron current and energy output
Surface area of electrodes
Likely hypothesis/ expected trend
It would be expected that the higher surface area electrodes would have a higher energy output
Similarity to the depth of the electrodes, higher surface area means that there is more contact between metals, ions and electrons, eliciting a higher electron current and energy output
NOT chosen due the the difficulty of accurately changing and measuring the surface area of the electrodes, as the electrodes would likely come with a defined size
10
20
30
Concentration of electrolyte solution
https://chemistry.stackexchange.com/questions/124702/electrochemistry-conditions-for-voltage-to-increase-in-a-galvanic-cell#:~:text=In%20an%20electrochemical%20cell%2C%20increasing,observed%20as%20a%20higher%20voltage
.
0.2
0.3
0.1
While this factor would increase the reaction rates in the cell and the energy output, it is time consuming to accurately prepare different concentrations of standard solutions.
Likely hypotheiss/expected trend
Increasing the concentration of electrolyte solution increases the rate of reaction at the electrodes and subsequently the electric current
Distance between electrodes
Likely hypothesis/ expected trend
https://chemistry.stackexchange.com/questions/35186/why-does-decreasing-the-distance-between-the-electrodes-in-an-electrolytic-cell#:~:text=Thus%2C%20by%20moving%20the%20electrodes,electrode%20%22sees%22%20is%20higher
.
By moving electrodes closer/ decreasing the length of the circuit , the resistance is decreased and voltage/energy output is increased
Chosen type of cell
Galvanic
This is because it is significantly easier to determine optimal energy output using a Voltmeter on a galvanic cell, than other means for the electrolytic cell. Electrolytic cells would require an energy input and the question is to design an electrochemical cell that produces an optimal energy output.
Possible anode cathode pairings
Zinc and Copper
This paring has been tested numerous times, ensuring testing. Both metals are readily unavailable and inexpensive. Due to being tested numerous times, the likelihood of a successful galvanic cell is high.
Zinc and Silver
This pairing is not chose due to the possible unavailability of silver in a school laboratory and the high expense of silver.