Question

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)

Part A

What is the rate constant at 641 ∘C ?

Express your answer to three significant digits with the appropriate units. For compound units, place a multiplication dot between units (e.g. J⋅mol−1⋅K−1).

Which of the following statements reasonably explains why this reaction has a low activation energy?

View Available Hint(s)

Which of the following statements reasonably explains why this reaction has a low activation energy?

The formal positive charge on the NO molecule is attracted to the formal negative charge on the F2 molecule, so the driving force for the formation of the transition state is greater than simple random collisions.

Due to the type of bonds being broken and formed in the transition state the stability of this transient structure is relatively high.

The electron-deficient NO molecule is attracted to the electron-rich F2 molecule, so the driving force for the formation of the transition state is greater than simple random collisions.

The small NO and F2 molecules have little steric hindrance; therefore random collisions occur more frequently.

Because this reaction is only bimolecular, the frequency of random collision is very high.

Answer 1

Sol :-

From Arrhenius equation :

k = A e ^-Ea/RT ................................(1)

Frequency factor = f = 6.00 x 10⁸ M^-1.s^-1

Activation energy = E_a = 6.30 kJ/mol

Temperature = T = 641 ⁰C = 914 K

R = Gas constant = 8.314 x 10^-3 KJ K^-1mol^-1 and

Rate constant = k = ?

Substitute all these values in equation (1), we have

k = ( 6.00 x 10⁸ M^-1.s^-1 ) x e ^{-(6.30 kJ/mol)/(8.314 x 10-3 KJ K-1 mol-1 x 914 K)]}

k = ( 6.00 x 10⁸ M^-1.s^-1 ) (0.4365)

k = 2.62 x 108 M-1s-1