21. Nuclear Chemistry

The accompanying graph illustrates the decay of ^{88}_{42}Mo, which decays via positron emission. What is the half-life of the decay?

Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute (CPM). If the half-life for carbon-14 is 5720 years, calculate the time it would take for the count rate to decrease to 6.8 CPM.

A 2.00 mg sample of the radioisotope phosphorus-32 is found to contain 0.400 mg of phosphorus-32 after 33.3 days. Calculate the half-life (in days).

The half-life of Strontium-85 is 65 days. How much of an 80 mg sample is left after 260 days?

How long will it take for 20% of the C-14 atoms in a sample of C-14 to decay, given that the half-life of C-14 is approximately 5730 years?

The half-life for the radioactive decay of C-14 is 5715 years and is independent of the initial concentration. How long does it take for 30.00% of the C-14 atoms in a sample of C-14 to decay?