Hydrogen peroxide is used as a bleachin agent, a disinfectant and medicinally as a topical antibacterial agent. Hydrogen peroxide decomposes according to the reacton
2H^2O^2(l)-->2H^2O(l)+o^2(g)
A. Given the standard free energy of formation values shown below, calculate the free energy change for this reaction.
Gf(H^2O^2)=-120.4kJ/mol
Gf(H^2O)=-237.1kJ/mol
answered above.
To calculate the free energy change (ΔG) for the given reaction, we need to use the equation:
ΔG = ΣnΔGf(products) - ΣmΔGf(reactants)
Where:
ΔG = Change in free energy (in kJ/mol)
Σn = Sum of coefficients of the products
ΔGf(products) = Standard free energy of formation for the products
Σm = Sum of coefficients of the reactants
ΔGf(reactants) = Standard free energy of formation for the reactants
Let's calculate the free energy change for the given reaction:
Given reactants:
H2O2 (l) → Coefficient = 2
ΔGf(H2O2) = -120.4 kJ/mol
Products:
H2O (l) → Coefficient = 2
ΔGf(H2O) = -237.1 kJ/mol
O2 (g) → Coefficient = 1
This is diatomic oxygen, so its standard free energy of formation is zero (ΔGf(O2) = 0 kJ/mol).
Now, we can substitute the values into the equation:
ΔG = ΣnΔGf(products) - ΣmΔGf(reactants)
= (2 × -237.1 kJ/mol) + (1 × 0 kJ/mol) - (2 × -120.4 kJ/mol)
Calculating the expression:
ΔG = (-474.2 kJ/mol) + (0 kJ/mol) + (240.8 kJ/mol)
= -474.2 kJ/mol + 240.8 kJ/mol
= -233.4 kJ/mol
Therefore, the free energy change for the reaction is -233.4 kJ/mol.