A 241 mg sample of carbon from a piece of cloth excavated from an ancient tomb in Nubia undergoes 1610 disintegrations in 11.4 h . If a current 1.00 g sample of carbon shows 921 disintegrations per hour, how old is the piece of cloth? (1 a=1 year)

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Suppose you found 80g of a glowing substance that was clearly radioactive. You put it in your pocket and went home with it, which took 1 hour. You measured the amount of radioactive material when you got home and discovered there was only 10g left. What is the half-life of this substance?

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 =

Radioactive vanadium-48 decays with a half-life of 16.0 days. a. What is the value of k in s? k = b. A sample contains 84.0 mg *°V. How many decay events will be produced in the first second? Assume the atomic mass of **V is 48.0 u. decays/s c. A chemist obtains a fresh sample of 48 V and measures its radioactivity. She then determines that to do an experiment, the radioactivity cannot fall below 25% of the initial measured value. How long does she have to do the experiment? days

Archeologists continue to debate the arrival of the first humans in the Western Hemisphere. Radiocarbon dating of charcoal from a cave in Chile was used to establish the earliest date of human habitation in South America as 8700 years ago. This procedure involves comparing the 14C present in a sample of charcoal to the 14C present in a living tree of the same age. What fraction of the 14C initially present remained in the charcoal after 8700 years? The half-life of 14C is 5730 years. (Write the answer as a number with a decimal.)

Americium-241 is widely used in smoke detectors. The radiation released by this element ionizes particles that are then detected by a charged-particle collector. The half-life of 241Am is 432 years, and 241 Am? it decays by emitting alpha particles. How many alpha particles are emitted each second by a 4.74-g sample of particles

A rock contains the radioactive isotope K − 40 that decays with a half-life of 1.3 billion years and the radioactive isotope Rb− 87 that decays with a half-life of 48.6 billion years. The rock is100 million years old. The rock currently has 1000 times as many Rb− 87 atoms as there are K − 40 atoms. (That is, N Rb= 1000 × N K) When the rock first formed it had M times as many Rb − 87 atoms as L − 40 atoms. (That is, N Rb, 0 = M × N K,0.) What is the value of M?

The half life for the decay of carbon-14 is 5.73 × 10³ years. Suppose the activity due to the radioactive decay of the carbon-14 in a tiny sample of an artifact made of wood from an archeological dig is measured to be 17. Bq. The activity in a similar-sized sample of fresh wood is measured to be 18. Bq. Calculate the age of the artifact. Round your answer to 2 significant digits. years x10 X

lodine-125 is a radioactive isotope commonly used in medicine. It has a half-life of 59.5 days. A sample contained 2.00 kg lodine-125 when it was made. How old is the sample when it contains 0.0625 kg Iodine- 125 (in days)?