It is found that a gas undergoes a first-order decomposition reaction. If the rate constant for this reaction is 8.1 x 10-2 /min, how long will it take for the concentration of the gas to change from an initial concentration of .1M to 1.0 x 10-2 M?

Respuesta :

Answer:

28.43 min

Explanation:

Using integrated rate law for first order kinetics as:

[tex][A_t]=[A_0]e^{-kt}[/tex]

Where,  

[tex][A_t][/tex] is the concentration at time t

[tex][A_0][/tex] is the initial concentration

Given that:

The rate constant, k = [tex]8.1\times 10^{-2}[/tex] min⁻¹

Initial concentration [tex][A_0][/tex] = 0.1 M

Final concentration [tex][A_t][/tex] = [tex]1.0\times 10^{-2}[/tex] M

Time = ?

Applying in the above equation, we get that:-

[tex]1.0\times 10^{-2}=0.1e^{-8.1\times 10^{-2}\times t}[/tex]

[tex]0.1e^{-8.1\times \:10^{-2}t}=10^{-2}[/tex]

[tex]e^{-8.1\times \:10^{-2}t}=\frac{1}{10}[/tex]

[tex]\ln \left(e^{-8.1\times \:10^{-2}t}\right)=\ln \left(\frac{1}{10}\right)[/tex]

[tex]t=28.43\ min[/tex]