231 A 60 mg sample of a radioactive isotope decays to 50 mg after 4.7 days....
A particular radioactive isotope decays from 190 milligrams (mg) to 152 mg in 15 days. Find the half life of the isotope. Hint: Find the rate first. The half life of the isotope is the half value of 190 mg then solve for x. Your answer is days.
(2 points) An unknown radioactive element decays into non-radioactive substances. In 520 days the radioactivity of a sample decreases by 63 percent. (a) What is the half-life of the element? half-life: (days) (b) How long will it take for a sample of 100 mg to decay to 84 mg? time needed: (days)
An unknown radioactive element decays into non-radioactive substances. In 760 days the radioactivity of a sample decreases by 77 percent.(a) What is the half-life of the element?half-life: (days)(b) How long will it take for a sample of 100 mg to decay to 68 mg?time needed: (days)
1. 1. Iodine-131 is a radioactive isotope. After 8.00 days, 50.2% of a sample of 131I remains. What is the half-life of 131I? 2. The half-lives of different radioisotopes are given in the table below. If the initial amount of potassium-44 is 9.2 g, how much potassium-44 is left in the body after 44 minutes? 2. 32P is a radioactive isotope with a half-life of 14.3 days. If you currently have 59.9 g of 32P, how much 32P was present...
A 100-mg sample of a radioactive isotope is obtained. After 33.5 minutes, only 3.10 mg remains. What is the half-life of the isotope? min
The Cadmium isotope 109Cd is radioactive. A sample begins decay with 1012 Cd atoms. After 500 days, 4.7 x 1011 atoms remain. What is the half-life of this sample? (a) 46 days (b) 102 days (c) 459 days -- right answer but not sure how to get it (d) 662 days (e) none of the above
A Radioactive sample contains 2.1g of an isotope with a half- life of 3.8 days. How much of the isotope in grams will remain after 10.0 days? Express the answer to 3 significant figures.
A 0.0116-g sample of a radioactive isotope with a half life of 1.3x109 years decays at the rate of 2.9x104 disintegrations per minute. Calculate the molar mass of the isotope. Enter your answer in scientific notation. (g/mol)
An initial amount of 100 g of the radioactive isotope thorium-234 decays according to Q(t) = 100e -0.02828t where t is in years. How long before half of the initial amount has disintegrated? This time is called the half-life of this isotope. (Round your answer to one decimal place.) yr
Radioactive gold-198 is used in the diagnosis of liver problems. The half-life of this isotope is 2.7 days. If you begin with a sample of 9.4 mg of the isotope, how much of this sample remains after 2.4 days?