2. The half-life of carbon-14 is 5,730 years. Express the amount of carbon-14 remaining as a function of time, t.

Radium-226 (atomic mass = 226.025402 amu) decays to radon-224 (a radioactive gas) with a half-life of 1.6 * 10^3 years. What volume of radon gas (at 25.0°C and 1.0 atm) does 25.0 g of radium produce in 5.0 days? (Report your answer to two significant digits.)

4. The half-life of radioactive radium-224 is 3.50 days. What was the original mass if 0.200 g remains after 10.50 days? A. 0.025 g B. 0.050 g C. 1.60 g D. 0.60 g

Cobalt-60 has a half-life of 5.27 years.  Considering a piece of that radioactive material, which percentage of it will be left  after 11.9 years? Keep three significant digits

Strontium-89 is a beta emitter with a half-life of 50.6 days that is used in bone cancer treatment. How many days will it take for a 69.6 mg sample of Sr-89 to decay to 0.148 mg?​ (Assume no excretion of the nuclide from the body).

Strontium-90 has a half life of 28 years. If a 5.31 mg sample was stored for 112 years, what mass of Sr-90 would remain?

The cesium-137 has a half life of 30 years after 90 years about 10g.remains. the original mass of cesium -137 is how much?

Iodine-125 is a radioactive isotope commonly used in medicine. It has a half-life of 59.5 days. Suppose at the start of Day 1 you store 3.77 kg of Iodine-125 in a cabinet and do not use it. After 119 days, how much Iodine-125 will you have (in kg)?

The half-life of carbon-14 is about 5730 years. If an ancient leather strap is about 11,500 years old, what percentage of carbon-14 in a now-living object remains in the strap? O 100% 50% O 25 % none O O O O