To calculate the activation energy Ea for the chemical reaction, we can use the Arrhenius equation:k = A * e^-Ea / RT where k is the rate constant 2.5 10^-3 s^-1 , A is the frequency factor 5 10^13 s^-1 , R is the gas constant 8.314 J/mol K , and T is the temperature 298 K .First, we need to isolate Ea in the equation:k / A = e^-Ea / RT Now, take the natural logarithm of both sides:ln k / A = -Ea / RTNext, multiply both sides by -RT:Ea = -RT * ln k / A Now, plug in the values:Ea = - 8.314 J/mol K * 298 K * ln 2.5 10^-3 s^-1 / 5 10^13 s^-1 Ea 96452.5 J/molThe activation energy for the chemical reaction is approximately 96,452.5 J/mol.