Problem: Calculate the standard entropy, ΔS°rxn, of the following reaction at 25.0°C using the data in this table. The standard enthalpy of the reaction, ΔH°rxn, is -633.1 kJ•mol-1. 3C2H2(g) → C6H6(I) ΔS°rxn =Then, calculate the standard Gibbs free energy of the reaction, ΔG°rxn.ΔG°rxn = Finally, determine which direction the reaction is spontaneous as written at 25.0°C and standard pressure. a. forward b. reverse c. both d. neither

FREE Expert Solution

For this problem, we need to solve for ΔS°rxn, ΔG°rxn, and determine which direction the reaction is spontaneous. 

For the reaction at T = 25.0°C: 

3C2H2(g) → C6H6(I)

The ΔH°rxn = -633.1 kJ•mol-1 (or kJ/mol) 


Recall that the equation for the standard entropy, ΔS°rxn is:

S°rxn = S°products - S°reactants

The standard free energy change of a reaction (ΔG˚rxn) is given by the following equation:


G°rxn = H°rxn-TS°rxn

From the given table, we can find the ΔS˚ of each reactant and product and use these values to calculate ΔS˚rxn

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Problem Details

Calculate the standard entropy, ΔS°rxn, of the following reaction at 25.0°C using the data in this table. The standard enthalpy of the reaction, ΔH°rxn, is -633.1 kJ•mol-1

3C2H2(g) → C6H6(I) 

ΔS°rxn =

Then, calculate the standard Gibbs free energy of the reaction, ΔG°rxn.

ΔG°rxn = 

Finally, determine which direction the reaction is spontaneous as written at 25.0°C and standard pressure. 

a. forward 

b. reverse 

c. both 

d. neither

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