There was a sample containing 1000 atoms of curium-243. After 120 years only 60 atoms of...
There was a sample containing 1000 atoms of curium-243. After 120 years only 60 atoms of this isotope were found in this sample. What is a half-life of curium-243? (answer is 30 years)
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There was a sample containing 1000 atoms of curium-243. After
120 years only 60 atoms of...
A freshly prepared sample of a certain radioactive isotope has an activity of 10.0 mCi. After...
A freshly prepared sample of a certain radioactive isotope has an activity of 10.0 mCi. After 3.80 h, the activity is 8.30 mCi. (a) Find the decay constant and half-life of the isotope. (b) How many atoms of the isotope were contained in the freshly prepared sample? (c) What is the sample's activity 30 h after it is prepared?
The barium isotope 133Ba has a half-life of 10.5 years. A sample begins with 1.1×1010 133Ba...
The barium isotope 133Ba has a half-life of 10.5 years. A sample begins with 1.1×1010 133Ba atoms. How many are 133Ba atoms left in the sample after 4 years. Express your answer using two significant figures. How many are 133Ba atoms left in the sample after 30 years. Express your answer using two significant figures. How many are 133Ba atoms left in the sample after 190 years. Express your answer using two significant figures.
The Cadmium isotope 109Cd is radioactive. A sample begins decay with 1012 Cd atoms. After 500...
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
1. The half-life of carbon-14 is 5730 years. A sample is found to have one-eighth the...
1. The half-life of carbon-14 is 5730 years. A sample is found to have one-eighth the original amount of carbon-14 in it. How old is the sample? 5730 years, 716 years, 45800 years, 17200 years 2. Why wouldn't you use carbon-14 dating on a piece of shell that was estimated to be 1 million years old? Sea shells do not have radioisotopes, carbon dating is only useful on plants, uranium dating is better for items older than 1/2 million years,...
An isotope of cesium (Cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137...
An isotope of cesium (Cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? 14. Thallium-208 has a half-life of 3.053 min. How long will it take for 120.0g to decay to 7.500 15. Element-106 has a half-life of 0.90 seconds. If one million atoms of it were prepared, how many atoms would remain after 4.5 seconds? 16. A 2.5 gram sample of an...
The Cs-131 nuclide has a half-life of 30 years. After 120 years, 8.7 g remain. What...
The Cs-131 nuclide has a half-life of 30 years. After 120 years, 8.7 g remain. What is the original mass of the Cs-131 sample?
A 100-mg sample of a radioactive isotope is obtained. After 33.5 minutes, only 3.10 mg remains....
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
231 A 60 mg sample of a radioactive isotope decays to 50 mg after 4.7 days....
231 A 60 mg sample of a radioactive isotope decays to 50 mg after 4.7 days. a) Determine the half-life. b) How long will it take for the amount of the isotope to decrease to 20 mg?
A pure sample of 226Ra contains 2.6 × 1013 atoms of the isotope. If the half-life...
A pure sample of 226Ra contains 2.6 × 1013 atoms of the isotope. If the half-life of 226Ra = 1.6 × 103 years, what is the decay rate of this sample? (1 Ci = 3.7 × 1010 decays/s)
The cadmium isotope 109Cd has a half-life of 462 days. A sample begins with 1.0×1012109Cd atoms...
The cadmium isotope 109Cd has a half-life of 462 days. A sample begins with 1.0×1012109Cd atoms How many 109Cd atoms are left in the sample after 340 days? How many 109Cd atoms are left in the sample after 5200 days?
An isotope of cesium (Cesium-137) has a half-life of 30 years. If 1.0 mg of cesium-137 disintegrates over a period of 90 years, how many mg of cesium-137 would remain? 14. Thallium-208 has a half-life of 3.053 min. How long will it take for 120.0g to decay to 7.500 15. Element-106 has a half-life of 0.90 seconds. If one million atoms of it were prepared, how many atoms would remain after 4.5 seconds? 16. A 2.5 gram sample of an...
The Cs-131 nuclide has a half-life of 30 years. After 120 years, 8.7 g remain. What is the original mass of the Cs-131 sample?
231 A 60 mg sample of a radioactive isotope decays to 50 mg after 4.7 days. a) Determine the half-life. b) How long will it take for the amount of the isotope to decrease to 20 mg?
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