The half-life of nobelium-259 is 58 minutes. Suppose we have an 80 mg sample. Find a formula for the mass remaining of the form m(t) =m0ekt where t is in minutes. Then find how much of the sample remains after 2 hours and how long it will take until 30 mg remain

Iodine-131 is used in the diagnosis and treatment of thyroid disease and has a half-life of 8.0 days. If a patient with thyroid disease consumes a sample of Na 131 I containing 10. μ g 131 I, how long will it take for the amount of 131 I to decrease to 1/100 of the original amount?

The half-life of strontium -90 is 28 years. How long will it take a 40 mg sample to decay to a mass of 10 mg? Your answer is years,

The half-life of carbon-14, an isotope used in archaeological dating, is 5730 years. What percentage of 14 6C remains in a sample estimated to be 17,000 years old?

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. Calculate the amount of americium-241 consumed in a smoke detector (initially containing 2.1000 µg of Am), in micrograms, that has been used for 1.000 year if the half-life is 433 years.

Americium-241 is widely used in smoke detectors. Calculate the amount of americium-241 consumed in a smoke detector (initially containing 3.60 µg of Am), in micrograms, that has been used for one year if the half-life is 433 years.