The remnants of an ancient fire in a cave in africa showed a 146C decay rate of 3.9 counts per minute per grams of carbon. if the decay rate in C-14 in freshly cut wood, is 13.6 counts per mintue per gram of carbon, how many years ago did the campfire occur?

Carbon-14 has a half-life of 5730 yr. The decay rate of 14C in fresh wood is 13.6 counts per minute per gram. A geologist finds a sample of petrified wood that has a 14C decay rate of 6.75 counts per minute per gram. How old is the piece of petrified wood, in years? Age:

A volcanic eruption melts a large chunk of rock, and all gases are expelled. After cooling, argon- 40 accumulates from the ongoing decay of potassium-40 (half-life of potassium-40 is 1.25 x 10° yr) in the rock. When a piece of rock is analyzed, it is found to contain 1.38 mmol of potassium- 40 and 1.14 mmol of argon-40. How long ago did the rock cool?

An archaeologist finds some ancient jewelry made from bone. The jewelry has a carbon mass of 484 g (HINT: Assume all the carbon is 12C and determine the number of atoms, 12C has a molar mass of 12 g/mol) and careful measurements show that the remaining 14c has a current decay rate of 11 decays/s. Determine the age of the bone (and presumably the jewelry). The ratio of 14C to 12c when the animal died was 1.25x10-12 & the half-life of 14c is 5730 y. Additionally, 1 mol = 6.022x1023 365.25 days, & 1 day = 24 h. particles, 1 y = age of bone =