Molecular iodine, I2(g), dissociates into iodine atoms at 625 K with a first-order rate constant of…

Molecular iodine, I2(g), dissociates into
iodine atoms at 625 K with a first-order rate constant of 0.271
s-1.
(a) What is the half-life for this reaction?
_______ s
(b) If you start with 0.051 M I2 at this
temperature, how much will remain after 5.30 s assuming that the
iodine atoms do not recombine to form I2?
_______ M