Calculate the standard reaction Gibbs energy of the oxidation of ammonia to
nitric oxide according to the equation
4 NH3g) + 5O2(g) → 4 No(g) + 6 H2O(g).
To calculate the standard reaction Gibbs energy (∆G°) of the oxidation of ammonia to nitric oxide, you can use the equation:
∆G° = Σn∆G°f(products) - Σm∆G°f(reactants)
Where:
- ∆G° is the standard reaction Gibbs energy.
- Σn∆G°f(products) is the sum of the standard molar Gibbs energy of formation (∆G°f) of the products, each multiplied by their stoichiometric coefficient.
- Σm∆G°f(reactants) is the sum of the standard molar Gibbs energy of formation (∆G°f) of the reactants, each multiplied by their stoichiometric coefficient.
Now, let's find the standard reaction Gibbs energy step by step:
1. Look up the standard molar Gibbs energy of formation (∆G°f) for each compound involved in the reaction. These values are usually reported in tables for standard conditions (usually at 298 K and 1 atm).
Here are the values for the compounds involved:
- ∆G°f(NH3(g)) = -16.5 kJ/mol
- ∆G°f(O2(g)) = 0 kJ/mol
- ∆G°f(NO(g)) = 87.6 kJ/mol
- ∆G°f(H2O(g)) = -228.6 kJ/mol
2. Write the balanced equation and include the stoichiometric coefficients for each compound:
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)
3. Calculate the Σn∆G°f(products) for the products by multiplying each ∆G°f value by its stoichiometric coefficient and summing them up:
Σn∆G°f(products) = (4 * ∆G°f(NO(g))) + (6 * ∆G°f(H2O(g)))
Σn∆G°f(products) = (4 * 87.6 kJ/mol) + (6 * -228.6 kJ/mol)
4. Calculate the Σm∆G°f(reactants) for the reactants by multiplying each ∆G°f value by its stoichiometric coefficient and summing them up:
Σm∆G°f(reactants) = (4 * ∆G°f(NH3(g))) + (5 * ∆G°f(O2(g)))
Σm∆G°f(reactants) = (4 * -16.5 kJ/mol) + (5 * 0 kJ/mol)
5. Substitute the values for Σn∆G°f(products) and Σm∆G°f(reactants) into the ∆G° equation:
∆G° = Σn∆G°f(products) - Σm∆G°f(reactants)
6. Calculate the ∆G° using the values from steps 3 and 4:
∆G° = [(4 * 87.6 kJ/mol) + (6 * -228.6 kJ/mol)] - [(4 * -16.5 kJ/mol) + (5 * 0 kJ/mol)]
After substituting the values and performing the calculations, you will obtain the standard reaction Gibbs energy (∆G°) of the oxidation of ammonia to nitric oxide.