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Concept explainers
Interpretation:
The
Concept introduction:
Activity is defined as the product of rate constant and number of atoms. It is also defined as the rate of decay or expresses number of atoms decays in unit time.
The mathematical expression is given by:
Where, A = activity, k = first order rate constant and N = number of radioactive nuclei.
Activity can be expressed in following units:
1 Bq = 1 atom/s
1 Ci = 3.700 × 1010 atoms/s
The mathematical expression is given by:
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Chapter 18 Solutions
Chemistry: Principles and Reactions
- Fluorine-18 is a radioactive isotope that decays by positron emission to form oxygen-18 with a half-life of 109.7 min. (A positron is a particle with the mass of an electron and a single unit of positive charge; the equation is F918O188+e+10 Physicians use 18F to study the brain by injecting a quantity of ?uoro-substituted glucose into the blood of a patient. The glucose accumulates in the regions where the brain is active and needs nourishment. (a) What is the rate constant for [lie decomposition of ?uorine-18? (b) If a sample of glucose containing radioactive fluorine-18 is injected into the blood, what percent of the radioactivity will remain after 5.59 h? (c) How long does it take for 99.99% of the 18F to decay?arrow_forwardThe rate constant for the radioactive decay of 14C is 1.21104 year-1. The products of the decay are nitrogen atoms and electrons (beta particles): C614N714+e rate =k[C614] What is the instantaneous rate of production of N atoms in a sample with a carbon-14 content of 6.5109M?arrow_forwardCarbon-14 (C-14) with a half-life of 5730 years decays to nitrogen-14 (N-14). A sample of carbon dioxide containing carbon in the form of C-14 only is sealed in a vessel at 1.00-atmosphere pressure. Over time, the CO2 becomes NO2 through the radioactive decay process. The following equilibrium is established: 2NO2(g)N2O4(g) If the equilibrium constant for the equation as written is 1105 , what is the pressure of N2O4 after 20,000 years? Assume that the CO2 does not participate in any chemical reactions.arrow_forward
- The streptomycin in 500 g of a broth was determined by addition of 1.25 mg of the pure antibiotic containing 14C. The specific activity of this preparation was found to be 240 cpm/mg for a 30-min count. From the mixture, 0.112 mg of purified streptomycin was isolated which produced 675 counts in 60.0 min. Calculate the concentration in parts per million streptomycin in the sample.arrow_forwardWhat is the half-life for the first-order decay of phosphorus-32? (P1532S1632+e) The rate constant for the decay is 4.85102 day-1.arrow_forwardIodine-131 is used to treat tumors in the thyroid. Its decomposition is first-order with a half-life of 8.1 days. If a patient is given a sample containing 5.00 mg of I-131, how long will it take for 32% of the isotope to remain in her system?arrow_forward
- Chemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning
- Chemistry & Chemical ReactivityChemistryISBN:9781337399074Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage LearningChemistry & Chemical ReactivityChemistryISBN:9781133949640Author:John C. Kotz, Paul M. Treichel, John Townsend, David TreichelPublisher:Cengage Learning
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