Glucose is the major fuel for most living cells. The...

Glucose is the major fuel for most living cells. The oxidative breakdown of glucose by our body to produce energy is called respiration. The reaction for the complete combustion of glucose is $$C_{6} \mathrm{H}_{12} \mathrm{O}_{6}(s)+6 \mathrm{O}_{2}(g) \longrightarrow 6 \mathrm{CO}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(l)$$ If this combustion reaction could be harnessed as a fuel cell, calculate the theoretical voltage that could be produced at standard conditions. (Hint: Use $\Delta G_{\mathrm{f}}^{\circ}$ values from Appendix $4 . )$

Glucose is the major fuel for most living cells. The oxidative breakdown of glucose by our body to produce energy is called respiration. The reaction for the complete combustion of glucose is
$$C_{6} \mathrm{H}_{12} \mathrm{O}_{6}(s)+6 \mathrm{O}_{2}(g) \longrightarrow 6 \mathrm{CO}_{2}(g)+6 \mathrm{H}_{2} \mathrm{O}(l)$$
If this combustion reaction could be harnessed as a fuel cell, calculate the theoretical voltage that could be produced at standard conditions. (Hint: Use $\Delta G_{\mathrm{f}}^{\circ}$ values from Appendix $4 . )$

Key Concepts

Reaction Stoichiometry and Electron Transfer

Understanding reaction stoichiometry is essential for correctly determining the number of electrons exchanged during the redox process in a fuel cell. The stoichiometric coefficients in a balanced chemical reaction help identify the total electron transfer number (n), which is necessary for applying the ?G = -nFE equation to compute the cell's theoretical voltage.

Standard Conditions and Free Energy of Formation

Standard conditions refer to a set of standard state parameters (typically 1 bar pressure, 25°C, and specified concentrations) under which thermodynamic data such as the standard free energy of formation are defined. These values are crucial for calculating the overall Gibbs free energy change of a reaction under standard conditions, allowing for the prediction of cell potential in fuel cell applications.

Electrochemical Cell Potential

The cell potential (or voltage) of an electrochemical reaction is determined by the change in Gibbs free energy and the number of electrons transferred in the reaction, as given by the relation ?G = -nFE. This relationship allows one to theoretically calculate the voltage produced by a fuel cell based on the free energy change of the reaction and the appropriate number of electrons involved in the overall reaction.

Gibbs Free Energy (?G)

Gibbs free energy is a thermodynamic quantity that measures the maximum reversible work that can be performed by a system at constant temperature and pressure. It is fundamental in determining the spontaneity of chemical reactions and is used to calculate the electrical work extractable from a fuel cell. In fuel cell calculations, the change in Gibbs free energy is directly related to the cell potential, linking chemical reaction energetics to electrical energy output.

Transcript

Please give Ace some feedback