If a tree dies and the trunk remains undisturbed for 1.500 × 10⁴ years, what percentage of the original ¹⁴C is still present? (The half-life of ¹⁴C is 5730 years.)

(2) What is the mass defect of a He atom if the atomic mass is 4.002603 amu? Answer: --- mass defect 0.030377 amu Am = (3) What mass of fuel must be consumed in a nuclear reactor to produce 36 x 10 Joules? (4) If 5 kg of fuel is consumed in a nuclear reactor how much energy is released?

The mass defect for potassium-40 is: -___x10-28kg. (Give your answer with 3 sig digs and do not include units) Use mass of proton = 1.007276 u mass of neutron = 1.008665 u actual mass = 39.9687 u

[Review Topics] [References] Radioactive vanadium-48 decays with a half-life of 16.0 days. a. What is the value of k in s12 k = b. A sample contains 58.0 mg 48 t° V. How many decay events will be produced in the first second? Assume the atomic mass of 48 V is 48.0 u. decays/s c. A chemist obtains a fresh sample of 8V 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 Submit Answer Retry Entire Group 4 more group attempts remaining