Consider a certain reaction A → Products with k = 2.0 × 10−2 s−1. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L−

Question 4.24: Consider a certain reaction A → Products with k = 2.0 × 10⁻² s⁻¹. Calculate the concentration of A remaining after 100 s if the initial concentration of A is 1.0 mol L⁻¹.
Answer
Given that
Rate constant, k = 2.0 × 10⁻² s⁻¹
Unit of rate constant is s^-1 so it is a first order reaction
Time period, t = 100 s
Initial concentration, [A]_o = 1.0 moL⁻¹
Use the formula of first order reaction we get

Plug the values in this formula we get
Use formula log x/ y = log x - log y, and plug log 1 = 0 we get

 solve it  and take antilog both side, we get
[A]= 0.135 mol L⁻¹ (approx)
Answer
Remaining concentration of A = 0.135 mol L⁻¹