True or false? (explain) (a) Because Arrhenius equation contains the gas constan

Question

True or false? (explain)

(a) Because Arrhenius equation contains the gas constant R, the Ar-rhenius equation applies only to gas-phase reactions.

(b) The Arrhenius equation holds exactly.

(c) The pre-exponential factor A has the same units for all reactions.

(d) In homogeneous catalysis, the catalyst does not appear in the rate law.

(e) In homogeneous catalysis, doubling the catalyst concentration will not change the rate.

(f) A catalyst does not appear in the overall reaction.

(g) In homogeneous catalysis, the catalyst does not appear in any of the steps of the mechanism.

Please explain so I can understand why :)

Explanation / Answer

(a) Because Arrhenius equation contains the gas constant R, the Arrhenius equation applies only to gas-phase reactions. This statement is FALSE

Explanation: As the Arrhenius equation.

k = Ae-Ea/RT

R is called gas constant but it has applicability on liquids or solids also. During the study of gases, R was first discovered and known as gas constant. Arhenius equation is applicable for all phases and not just gas. Though, R is related to two other constants: Boltzmann's constant kB and Avogadro's number NA.

                                                   R= NA * kB

We do not use kB very often because it is more suitable for small numbers of particles. An exponential term e-Ea/RT is a probability function which is the same regardless of phases.

(b) False.

The Arrhenius equation is temperature (T) dependent as T changes, the term e(-Ea/RT) will also change. Thus the reaction would be an endothermic process or an exothermic process as the term -Ea/RT is not constant with changing temperature.
© False.

According to the Arrhenius equation, a rate constant k is the product of a pre- exponential ("frequency") factor A and an exponential term e-Ea/RT. The pre-exponential factor or Arrhenius constant (A) has the same unit as the unit of the rate constant (k).

D) False

In reaction mechanism, a catalyst will always appear in reaction. A catalyst is speed up the rate of chemical reaction.

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