Calculate the standard entropy change for the following reaction.
2 Al(s) + Fe2O3(s) → 2 Fe(s) + Al2O3(s)
This is a Hess's Law Equation problem... Add the enthalpy's of formation for the products minus the enthalpy's of formation of the products.
The same answer but another way is
dHrxn = (n*dHr products) - (n*dHf reactants)
To calculate the standard entropy change (ΔS°) for the given reaction, you need to consider the standard entropy values of the reactants and products involved in the reaction.
The standard entropy change (ΔS°) can be calculated using the equation:
ΔS° = ΣS°(products) - ΣS°(reactants)
First, you need to determine the standard entropy values (S°) for each of the species involved in the reaction. These values can be found in thermodynamics tables or reference sources. Here are the standard entropy values for the given species:
ΔS°(Al) = 28.3 J/(mol·K)
ΔS°(Fe2O3) = 87.4 J/(mol·K)
ΔS°(Fe) = 27.3 J/(mol·K)
ΔS°(Al2O3) = 50.9 J/(mol·K)
Next, substitute these values into the equation to calculate the standard entropy change:
ΔS° = [2ΔS°(Fe) + ΔS°(Al2O3)] - [2ΔS°(Al) + ΔS°(Fe2O3)]
ΔS° = [2(27.3 J/(mol·K)) + 50.9 J/(mol·K)] - [2(28.3 J/(mol·K)) + 87.4 J/(mol·K)]
Now, calculate the values inside the brackets:
ΔS° = [54.6 J/(mol·K) + 50.9 J/(mol·K)] - [56.6 J/(mol·K) + 87.4 J/(mol·K)]
ΔS° = 105.5 J/(mol·K) - 144 J/(mol·K)
Finally, subtract the value inside the brackets to find the standard entropy change:
ΔS° = -38.5 J/(mol·K)
Therefore, the standard entropy change for the given reaction is -38.5 J/(mol·K).