Question

Hi, The gas-phase reaction of NO with F2 to form NOF and F has an activation energy of Ea = 6.30 kJ/mol and a frequency factor of A = 6.00×108 M−1⋅s−1 . The reaction is believed to be bimolecular: NO(g)+F2(g)→NOF(g)+F(g).What is the rate constant at 685 ∘C ?

Answer 1

According to the Arrhenius equation, the rate constant of the reaction is:

$k = A·e^{-\frac{E_a}{RT}}$ ,

where $A$ is the frequency factor (more precisely, it is the pre-exponential factor), $E_a$ is the activation energy, $R$ is the ideal gas constant (8.314 J/(K·mol)) and $T$ is the absolute temperature (in kelvin, 685°C is (685+273.15) = 958 K). Therefore:

$k = 6.00·10^8·e^{-\frac{6.30·10^3}{8.314·958}} = 2.72·10^8$ M^-1s^-1.

Answer: the rate constant is 2.72·10⁸ M^-1s^-1.