decomposition reaction?

Question

Given data to find 1) the rate constant for the process 2) how long would it take for Yuck-1 decompose to its "safe" level of 0.06g

Time (hrs) 0 1 2 3 4 5 6
Mass remaining (g) 6.0 4.24 3.0 2.12 1.5 1.11 0.75

Answer 1

M = Mo(1/2)^(t/2)
6(1/2)^(t/2) = 0.06
(1/2)^(t/2) = 0.01
(t/2)log(1/2) = log(0.01)
t = 2(-2)/-0.30103
t = 13.3 hr.