Respuesta :
The integrated rate law for a second-order reaction is given by:
[tex] \frac{1}{[A]t} = \frac{1}{[A]0} + kt [/tex]
where, [A]t= the concentration of A at time t,
[A]0= the concentration of A at time t=0
k = the rate constant for the reaction
Given: [A]0= 4 M, k = 0.0265 m–1min–1 and t = 180.0 min
Hence, [tex] \frac{1}{[A]t} = \frac{1}{4} + (0.0265 X 180) [/tex]
= 4.858
Therefore, [A]t= 0.2058 M.
Answer: Concentration of A, after 180 min, is 0.2058 M
Answer: 0.199M
Explanation:
1) An initial clarification: the unit of the concentration is M (molarity) and not m as it was written in the question (m is used for molality, and that is other unit of concentration).
2) Second order reaction means that the rate of reaction is given by:
r = - d[A]/dt = [A]²
3) By integration you get:
1 / [A] - 1[Ao] = kt
=> 1 / [A] = 1 / [Ao] + kt
4) Plug in the data; [Ao] = 4.00M; k = 0.0265 (M⁻¹) (min)⁻¹; t = 180 min
=> 1 / [A] = 1 / 4.00M + 0.0265 (M⁻¹)(min⁻¹) (180min) = 5.02 (M⁻¹)
=> [A] = 1 / (5.02(M⁻¹) = 0.199 M
Explanation:
1) An initial clarification: the unit of the concentration is M (molarity) and not m as it was written in the question (m is used for molality, and that is other unit of concentration).
2) Second order reaction means that the rate of reaction is given by:
r = - d[A]/dt = [A]²
3) By integration you get:
1 / [A] - 1[Ao] = kt
=> 1 / [A] = 1 / [Ao] + kt
4) Plug in the data; [Ao] = 4.00M; k = 0.0265 (M⁻¹) (min)⁻¹; t = 180 min
=> 1 / [A] = 1 / 4.00M + 0.0265 (M⁻¹)(min⁻¹) (180min) = 5.02 (M⁻¹)
=> [A] = 1 / (5.02(M⁻¹) = 0.199 M