8) The reaction

CH3- N≡C → CH3- C≡N

is a first-order reaction. At 230.3°C, k = 6.29 x 10^-4 s^- 1. If [CH3 -N≡ is 1.00 x 10^-3 initially,
C]

[CH3-N ≡ C] is __________ after 1.000 x 10^3 s.

A) 5.33 x 10^-4

B) 1.00 x 10^-6

C) 4.27 x 10^-3

D) 2.34 x 10^-4

E) 1.88 x 10^-3

ln(No/N) = kt

Substitute and solve for N.

To determine the concentration of [CH3-N ≡ C] after a given time, we can use the first-order rate equation:

[A] = [A0] * e^(-kt)

Where:
[A] is the concentration of [CH3-N ≡ C] at a given time
[A0] is the initial concentration of [CH3-N ≡ C]
k is the rate constant
t is the time

Given information:
Initial concentration [CH3-N ≡ C] ([A0]) = 1.00 x 10^-3
Rate constant (k) = 6.29 x 10^-4 s^-1
Time (t) = 1.000 x 10^3 s

Substituting the values into the equation:

[A] = (1.00 x 10^-3) * e^(-6.29 x 10^-4 * 1.000 x 10^3)

Using a calculator:

[A] ≈ 1.88 x 10^-3

Therefore, the concentration of [CH3-N ≡ C] after 1.000 x 10^3 s is approximately 1.88 x 10^-3.

So the correct option is E) 1.88 x 10^-3.