Chemical Kineti...

In a first order reaction, the concentration of the reactant, decreases from 0.8 M to 0.4 M in 15 minutes. The time taken for the concentration to change from 0.1 M to 0.025 M is: 

For a first order reaction, (A) $$\rightarrow$$ product, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M, is:

The time for half-life period of a certain reaction $$\mathrm{A}\rightarrow$$ products is 1 hour. When the initial concentration of the reactant $$A$$ is 2.0 mol L$$^{-1}$$, how much time does it take for its concentration to come from 0.50 to 0.25 mol L$$^{-1}$$ if it is a zero-order reaction?

The rate of a reaction quadruples when the temperature changes from 300 to 310 K. The activation energy of this reaction is :
(Assume activation energy and pre-exponential factor are independent of temperature; $$ln\ 2$$=0.693; R = 8.314 J $$mol^{ -1} K^{-1}$$) 

Higher order (>3) reactions are rare due to:

$$\mathrm{l}\mathrm{n}$$ a first order reaction the concentration of reactant decreases from 800 $$\mathrm{m}\mathrm{o}l/\mathrm{d}\mathrm{m}^{3}$$ to 50 $$\mathrm{m}\mathrm{o}l/\mathrm{d}\mathrm{m}^{3}$$ is $$2\times 10^{4}$$ sec. The rate constant of reaction in $$\sec^{-1}$$ is:

$$A$$ follows the first-order reaction.

Activation energy of a reaction:

The decomposition of phosphine $$(PH_3)$$ on tungsten at low pressure is a first-order reaction. It is because the:

A first order reaction has a specific reaction rate of $$10^{-2} sec^{-1}$$. How much time will it take for $$20\ g$$ of the reactant to reduce to $$5\ g$$?