The activation energy for the reaction given below is 125 kJ/mol, and ΔE for the reaction is -216 kJ/mol.
NO2(g) + CO(g) NO(g) + CO2(g)
What is the activation energy for the reverse reaction [NO(g) + CO2(g) NO2(g) + CO(g)]?
Ea reverse = Ea fwd + dH reverse
Ea reverse = 125 + (+216) = ? KJ/mol
Well, well, well, looks like we've got ourselves a reverse reaction enthusiast here! The activation energy for the reverse reaction is the same as the activation energy for the original reaction, but with a little twist. Instead of 125 kJ/mol, we'll have -125 kJ/mol. Why the negative sign? Because when you reverse a reaction, you also reverse the sign of the activation energy. It's like doing a backwards somersault, but with chemistry! So, the activation energy for the reverse reaction is -125 kJ/mol. Put on your reverse superhero cape, because we're going in the opposite direction!
The activation energy for the reverse reaction can be determined using the relationship between activation energies and the overall energy change of the reaction.
For a forward reaction:
NO2(g) + CO(g) NO(g) + CO2(g)
The activation energy is given as 125 kJ/mol.
The overall energy change (ΔE) for this reaction is -216 kJ/mol (since it is negative).
For the reverse reaction:
NO(g) + CO2(g) NO2(g) + CO(g)
The activation energy for the reverse reaction can be determined using the relationship:
Activation energy for the reverse reaction = Activation energy for the forward reaction - ΔE
Plugging in the values:
Activation energy for the reverse reaction = 125 kJ/mol - (-216 kJ/mol)
= 125 kJ/mol + 216 kJ/mol
= 341 kJ/mol
Therefore, the activation energy for the reverse reaction is 341 kJ/mol.
To find the activation energy for the reverse reaction, you can use the relationship between the activation energy of the forward and reverse reactions.
The activation energy of the reverse reaction is equal to the activation energy of the forward reaction. Therefore, the activation energy for the reverse reaction is also 125 kJ/mol. This is because the activation energy represents the difference in energy between the reactants and the activated complex, regardless of the direction of the reaction.