Help with Rate Constant Calculations?
The isomerization reaction CH3NC → CH3CN obeys the first-order rate law,
rate = k[CH3NC],
in the presence of an excess of argon. Measurement at 500. K reveals that in 485 seconds, the concentration of CH3NC has decreased to 73% of its original value. Calculate the rate constant (k) of the reaction at 500. K.
___s−1
(The integrated form for the first-order rate law can be written in the general terms
ln[A]t − ln[A]0 = −kt, where
[A]0
is the initial concentration of reactant A,
[A]t
is the concentration of A at time t, and k is the rate constant.)
The isomerization reaction CH3NC → CH3CN obeys the first-order rate law,
rate = k[CH3NC],
in the presence of an excess of argon. Measurement at 500. K reveals that in 485 seconds, the concentration of CH3NC has decreased to 73% of its original value. Calculate the rate constant (k) of the reaction at 500. K.
___s−1
(The integrated form for the first-order rate law can be written in the general terms
ln[A]t − ln[A]0 = −kt, where
[A]0
is the initial concentration of reactant A,
[A]t
is the concentration of A at time t, and k is the rate constant.)
2 Answers
Explanation:
The problem says that at t = 485 s,
Therefore
Consider,
The nitrile group is much more stable than the odd configuration nitrogen is in the first isomer of that molecule (it even has a formal charge).
Temperature in this case is merely descriptive and perhaps to illustrate that reaction rates are generally proportional to temperature.
This is a first order reaction. Recall,
Hence,
is the rate constant of this reaction given these data.