The activation energy of one of the reactions in a biochemical process is 532611 J mol^$$-$$1. When the temperature falls from 310 K to 300 K, the change in rate constant observed is k₃₀₀ = x $$\times$$ 10^$$-$$3 k₃₁₀. The value of x is ____________.

[Given : $$\ln 10 = 2.3$$, R = 8.3 J K^$$-$$1 mol^$$-$$1]

A radioactive element has a half life of 200 days. The percentage of original activity remaining after 83 days is ___________. (Nearest integer)

(Given : antilog 0.125 = 1.333, antilog 0.693 = 4.93)

For a first order reaction A $$\to$$ B, the rate constant, k = 5.5 $$\times$$ 10^$$-$$14 s^$$-$$1. The time required for 67% completion of reaction is x $$\times$$ 10^$$-$$1 times the half life of reaction. The value of x is _____________ (Nearest integer)

(Given : log 3 = 0.4771)

It has been found that for a chemical reaction with rise in temperature by 9 K the rate constant gets doubled. Assuming a reaction to be occurring at 300 K, the value of activation energy is found to be ____________ kJ mol^$$-$$1. [nearest integer]

(Given ln10 = 2.3, R = 8.3 J K^$$-$$1 mol^$$-$$1, log 2 = 0.30)