Answer:
0.0277 M.
Explanation:
The integral rate law of a first order reaction:
Kt = ln ([A₀]/[A]),
where, k is the rate constant of the reaction (k = 3.36 × 10⁻⁵ s⁻¹),
t is the time of the reaction (t = 235.0 min = 14100 s),
[A₀] is the initial concentration of cyclopropane ([A₀] = 0.0445 M)
∵ Kt = ln ([A₀]/[A]),
∴ (3.36 × 10⁻⁵ s⁻¹)(14100 s) = ln (0.0445 M)/[A]
Taking the exponential of both sides:
1.6 = (0.0445 M)/[A]
∴ [A] = (0.0445 M)/1.6 = 0.0277 M.
