Biomolecular Rate Theories

Question 1

What two factors influence collision frequency Zab

Answer 1

The cross sectional area of the two species and the relative velocity between the two

Question 2

Fraction of molecules with energy that meets Ea

Answer 2

F = exp(-Ea/kbT) Boltzmann distribution law

Question 3

Flaw with collision theory

Answer 3

Tends to over predict the rate constant as it does not take into account the internal structure or orientation of reactants

Question 4

Assumptions made for transition state theory

Answer 4

There exists a configuration of the nuclei of A and B which can spontaneously form both the reactants and the products. The transition state is in effective equilibrium with the reactants

Question 5

Units of collision theory rate constant

Answer 5

molecule-1cm3s-1

Question 6

What are the correct/standard units for A (Boltzmann)

Answer 6

mol-1m3s-1

Question 7

What thermodynamic terms occur in the transition state rate equation

Answer 7

Entropy and enthalpy of activation

Question 8

Activation energy of a bimolecular gas phase reaction

Answer 8

Ea = dH + 2RT where dH is the enthalpy of the transition state

Question 9

Whatare reasonable values for Gibbs and enthalpy of activation

Answer 9

Both must be positive. Energy is required to form the transition state the the transition is not spontaneous

Question 10

What the is the collision theory reaction rate a product of

Answer 10

The collision frequency and the fraction of collisions that meet the energy requirements of Ea

Question 11

Entropy of activation of a bimolecular gas phase reaction

Answer 11

dS = Rln(Ae^-2(hC/kbT))
where:
C is standard concentration

Question 12

What is standard concentration

Answer 12

1 molm-3