Q5(a). Activation energy from two rate constants

The gas-phase reaction between methane (CH₄) and diatomic sulphur (S₂) is given by CH₄(g) + 2S₂(g) → CS₂(g) + 2H₂S(g). At 823 K, the rate constant for this reaction is 1.1 × 10⁻³ m³ mol⁻¹ s⁻¹ and at 898 K, the rate constant is 6.4 × 10⁻³ m³ mol⁻¹ s⁻¹. Calculate the activation energy for this reaction. Given: R = 8.3145 J K⁻¹ mol⁻¹.