In a first-order decomposition reaction. 25.5% of a compound decomposes in 11.3 min. How long (in min) does it take for 82.3% of the compound to decompose?

Respuesta :

Answer:

66.5 min does it take for 82.3% of the compound to decompose.

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:

25.5 % is decomposed which means that 0.255 of [tex][A_0][/tex] is decomposed. So,

[tex]\frac {[A_t]}{[A_0]}[/tex] = 1 - 0.255 = 0.745

t = 11.3 min

[tex]\frac {[A_t]}{[A_0]}=e^{-k\times t}[/tex]

[tex]0.745=e^{-k\times 11.3}[/tex]

k = 0.02605 min⁻¹

Also,  

Given:

82.3 % is decomposed which means that 0.823 of [tex][A_0][/tex] is decomposed. So,

[tex]\frac {[A_t]}{[A_0]}[/tex] = 1 - 0.823 = 0.177

t = ?

[tex]\frac {[A_t]}{[A_0]}=e^{-k\times t}[/tex]

[tex]0.177=e^{-0.02605\times t}[/tex]

t = 66.5 min

66.5 min does it take for 82.3% of the compound to decompose.

66.5 min will take 82.3% of the compound to decompose.

What is the first-order reaction?

The first-order reaction rate depends on the concentration of one reactant.

By the first-order integrated rate law

[tex]\rm [At]= [A_0]e^-^k^t[/tex]

where [tex]\rm [A_0][/tex] is the initial concentration

[tex]\rm [At][/tex] is the concentration at time t

25.5% of a compound decomposes in 11.3 min.

So [tex]\rm [A_0][/tex] is 0.255

[tex]\rm \dfrac{[At]}{[A_0]} = 1- 0.255 = 0.745[/tex]

Time is 11.3 min.

[tex]\rm \dfrac{[At]}{[A_0]} =e^-^k^t\\\\\\\rm 0.745 =e^-^k^ \times^1^1^.^3\\\\k = 0.02605\; min^-^1[/tex]

82.3% of the compound to decompose

k =0.02605

t=?

[tex]\rm \dfrac{[At]}{[A_0]} = 1 - 0.823 = 0.177\\\\\rm \dfrac{[At]}{[A_0]} =e^-^k^t\\\\\\\rm 0.177 =e^-^0^.^0^2^6^0^5^ \times^t\\\\t = 66.5\; min^-^1[/tex]

Thus, 66.5 min will take 82.3% of the compound to decompose.

Learn more about first-order reaction, here:

https://brainly.com/question/13329678