The rate constant for a certain reaction is kkk = 3.50×10−3 s−1s−1 . If the initial reactant concentration was 0.450 MM, what will the concentration be after 19.0 minutes?

A zero-order reaction has a constant rate of 3.50×10−4 M/sM/s. If after 65.0 seconds the concentration has dropped to 3.50×10−2 MM, what was the initial concentration?

Respuesta :

Explanation:

Question 1

Rate constant = 3.50×10−3 s−1

Initial Concentration [A]o =  0.450 M

Final concentration [A] = ?

time = 19 minutes = 1140 s (upon conversion to seconds)

Integrated rate law for a first order reaction is given as;

ln[A] = ln[A]o - kt

ln[A] = ln (0.450) - (3.50×10−3)1140

ln[A] = -0.799 - 3.99

ln[A] = -4.789

[A] = 0.0083M

Question 2

Rate constant, k = 3.50×10−4 M/s

time = 65 s

Final Concentration [A] = 3.50×10−2 M

Initial Concentration [A]o = ?

Integrated rate law for a first order reaction is given as;

[A] = [A]o - kt

[A]o = [A] + kt

[A]o = 3.50×10−2 + (3.50×10−4) * 65

[A]o = 3.50×10−2 + 0.02275

[A]o = 0.05775 M

The rate law is defined as the amount of reactant present in the initial concentration and used up during the course of the reaction. The rate depends on the following:-

  • Amount
  • Pressure
  • Volume

According to the question, the expression of the rate is[tex]Rate = k[A][B][/tex] . As the data are given in the question, the rate constant is [tex]3.50×10^{-3}1/s[/tex] , the initial concentration[tex][A]_o = 0.450 M[/tex] and time is 19 minutes that is the 1140s.

We have to find the final concentration,  Integrated rate law for a first-order reaction is given as;

[tex]ln[A] = ln[A]_o - kt\\ln[A] = ln (0.450) - (3.50*10^-^3)1140\\ln[A] = -0.799 - 3.99\\ln[A] = -4.789\\[A] = 0.0083M[/tex]

For the second problem, the data given is as follows:-

  • Rate constant ,[tex]k = 3.50*10^-^4 M/s[/tex]
  • Time = 65 s
  • Final Concentration [A] = [tex]3.50*10^-^2 M[/tex]

We have to find the Initial Concentration, after solving the equation.

[tex][A] = [A]_o - kt[A]_o = [A] + kt\\[A]o = 3.50*10^{-2} + (3.50*10^{-4}) * 65\\[A]_o = 3.50*10^{-2} + 0.02275\\[A]_o = 0.05775 M[/tex]

Hence, the final concentration is 0.5775m.

For more information, refer to the link:-

https://brainly.com/question/14945022