Question

The rate constant for this first-order reaction is 0.450 s–1 at 400 °C. A -> products. How long (in seconds) would it take for the concentration of A to decrease from 0.820 M to 0.400 M?

Answer 1

use this formula \(\large [A]_t=[A]_o*e^{kt}\)

k=constant
t= time elapsed
\([A]_t\)= amount after t
\([A]_o\)=initial amount