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.