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6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂

a. Calculate ΔH°rxn at 15 °C.
b. Calculate ΔS°rxn at 15 °C.
c. Calculate ΔG°rxn at 15 °C.
d. Is it spontaneous?

1 Answer

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Final answer:

To calculate ΔH°rxn, use the standard enthalpy of formation values for the reactants and products. To calculate ΔS°rxn, use the standard entropy values. To calculate ΔG°rxn, use the equation ΔG°rxn = ΔH°rxn - TΔS°rxn. If ΔG°rxn is negative, the reaction is spontaneous.

Step-by-step explanation:

a. To calculate ΔH°rxn at 15 °C, you need to use the standard enthalpy of formation values for the reactants and products. The standard enthalpy of formation of CO₂ is -393.5 kJ/mol, H₂0 is -285.8 kJ/mol, C₆H₁₂O₆ is -1273.0 kJ/mol, and O₂ is 0 kJ/mol. Use the equation ΔH°rxn = Σ(nΔH°f(products)) - Σ(nΔH°f(reactants)), where n is the stoichiometric coefficient. Insert the values to obtain the final answer.

b. To calculate ΔS°rxn at 15 °C, you need to use the standard entropy values for the reactants and products. The standard entropy of CO₂ is 213.8 J/(mol·K), H₂0 is 69.9 J/(mol·K), C₆H₁₂O₆ is 212.6 J/(mol·K), and O₂ is 205.1 J/(mol·K). Use the equation ΔS°rxn = Σ(nΔS°(products)) - Σ(nΔS°(reactants)), where n is the stoichiometric coefficient. Insert the values to obtain the final answer.

c. To calculate ΔG°rxn at 15 °C, you need to use the equation ΔG°rxn = ΔH°rxn - TΔS°rxn, where T is the temperature in Kelvin. Insert the values from parts a and b to obtain the final answer.

d. To determine if the reaction is spontaneous, you need to calculate ΔG°rxn and compare it to zero. If ΔG°rxn is negative, the reaction is spontaneous. If ΔG°rxn is positive, the reaction is non-spontaneous.

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