1.Element Q has three isotopes. The first has a mass of 34.8636 amu and makes up 39.2 % of a standard sample. The second isotope has a mass of 36.5076 amu and makes up 43 % of a standard sample. The third isotope has a mass of 38.1639 amu and makes up the remainder of a standard sample. What is the average atomic mass of this element?
2. You want to do an experiment using 47Ca (half-life=4.53 days). You will need 3.95 μg of the nuclide. What mass of CaCO3 (100% enriched in 47Ca) must you order if it will take 37 hours to be delivered to you from the nuclear facility where it is prepared?
3.A living plant contains approximately the same isotopic abundance of 14C as does atmospheric carbon dioxide. The observed rate of decay of 14C from a living plant is 15.3 disintegrations per minute per gram of carbon. How many disintegrations per minute per gram of carbon will be measured from a 17000-year-old sample? (The half-life of 14C is 5730 years.)
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