# Exercise 10 | Chemical Kinetics: Rate Laws

Sample of oak from an ancient site have a carbon-14 content equal to 85.0 % that in living matter.

Estimate the age of the wood knowing that t1/2 (14C) = 5730 years.

Radioactive decay is a first-order process:

ln $\left(\frac{\mathrm{N}}{{\mathrm{N}}_{0}}\right)$ = -kt and t1/2

⇒ ln $\left(\frac{\mathrm{N}}{{\mathrm{N}}_{0}}\right)$ = -

⇒ t = ln $\left(\frac{{\mathrm{N}}_{0}}{\mathrm{N}}\right)$ x  = ln (100/85) x  = 1340 years