This question is about a glucose–oxygen fuel cell - AQA - A-Level Chemistry - Question 11 - 2020 - Paper 1
Question 11
This question is about a glucose–oxygen fuel cell.
When the cell operates, the glucose (C₆H₁₂O₆) molecules react with water at the negative electrode to form carbon... show full transcript
Worked Solution & Example Answer:This question is about a glucose–oxygen fuel cell - AQA - A-Level Chemistry - Question 11 - 2020 - Paper 1
Step 1
Deduce the half-equation for the reaction at the negative electrode.
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Answer
At the negative electrode, glucose reacts with water to produce carbon dioxide and hydrogen ions. The half-equation can be represented as:
C6H12O6+6H2O→6CO2+24H++24e−
Step 2
Deduce the half-equation for the reaction at the positive electrode.
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Answer
At the positive electrode, oxygen reacts with hydrogen ions to form water. The half-equation is:
O2+4H++4e−→2H2O
Step 3
Give the equation for the overall reaction that occurs in the Glucose–oxygen fuel cell.
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Answer
The overall reaction in the fuel cell combines the half-equations from the negative and positive electrodes:
C6H12O6+6O2→6CO2+6H2O
Step 4
Give the conventional representation for the glucose–oxygen fuel cell.
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Answer
The conventional representation of the glucose–oxygen fuel cell can be expressed as:
[C6H12O6]∣[CO2]∣[H+]∣[O2]∣[H2O]∣[Pt]
Step 5
State what must be done to maintain the EMF of this fuel cell when in use.
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Answer
To maintain the EMF of the fuel cell while in use, it is necessary to continuously add reactants, specifically glucose and oxygen, or keep the concentration of reactants constant.
