A decomposition reaction has a rate constant of 0.0019 yr -1.

Question

(
a) What is the half-life of the reaction?
______ yr

(b) How long does it take for [reactant] to reach 12.5% of its original value?
______ yr

Answer 1

a)
k = 0.693/t_1/2
Substitute and solve for t_1/2

b)
ln(No/N) = kt
If you let No = 100, then N = 12.5; substitute k and solve for t in years.

Answer 2

.0013167