1. The problem statement, all variables and given/known data Background info: The first order rate of nuclear decay of an isotope depends only upon the isotope, not its chemical form or temperature. The half-life for decay of carbon-14 is 5730 years. Assume that the amount of C-14 present in the atmosphere as CO2 and therefore in a living organism has been constant for the last 50,000 years. An ancient sample containing C-14 will show fewer disintegrations of the C-14 that is present than a modern sample because the concentration of C-14 is lower in the ancient sample. If a 1.00 gram sample of wood found in an archaelogical site in Arizona underwent 7.90x103 disintegrations in a given time period (e.g., 20 h) and a modern sample underwent 1.84x104 disintegrations in the same time period, how old is the ancient sample? 2. Relevant equations First order: ln[A]t = -kt + ln[A]o [A]t = e-kt[A]o ln(([A]o/2)/[A]o) = -kt1/2 = ln(1/2) or ln2 = kt1/2 = 0.693 3. The attempt at a solution kt1/2 = 0.693 k = 0.693/5730 = 1.21x10-4 ln[A]t = -kt + ln[A]o ln[A]t = ? ln[A]o = ? Solve for t? Is this the right equation to use?