Nickel-57 undergoes β+ decay (t1/2 = 36.0 hr) to form cobalt-57. How long will it take for 0.150 mol of cobalt-57 to form from 1.25 mol of nickel-57?

Hydrogen-3 has a half-life of 12.3 years. How many years will it take for 502.0 mg ^3H to decay to 0.49 mg ^3H?

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.)

Nickel-63 undergoes β decay (t1/2 = 92. yr) to form copper-63. How long will it take for 1.150 mol of copper-63 to form from 1.250 mol of nickel-63? Group of answer choices - 340yr -17yr -980yr -170yr -120yr

Three radioisotopes X, Y, and Z have half-lives of 1, 2 and 5 years respectively. Each of the three radioisotopes has the same activity now in July 2020. Which radioisotope will be hotter (meaning it will have more activity remaining) if you were to examine them at different times in the future, specifically in July 2023 for X, July 2024 for Y, and July 2040 for Z? Provide a full explanation of your reasoning. O Y because 2 half-lives will have passed by July 2024. OX because July 2023 is sooner than July 2024 or July 2040. OX because 3 half-lives will have passed by July 2023. O Z because July 2023 is sooner than July 2024 or July 2040. Z because July 2040 is later than July 2023 and July 2024. O Y because July 2023 is sooner than July 2024 or July 2040. O Z because 4 half-lives will have passed by July 2040.