4) A chemical substance has a decay rate of 9.3% per day. The rate of change of an amount, N, of the chemical after t days is given by = -0.093N. dt a. Suppose that 500 grams of the substance is present at timet = 0. Find the function, N(t), that models the decay. b. How many grams of the chemical will remain after 12 days? Round to the nearest hundredth of a gram. c. What is the "half-life" of this this substance? Round to the nearest day when no more than half remains. d. Calculate N'(2) and interpret the result in context.

4) A chemical substance has a decay rate of 9.3% per day. The rate of change of an amount, N, of the chemical after t days is given by = -0.093N. dt a. Suppose that 500 grams of the substance is present at timet = 0. Find the function, N(t), that models the decay. b. How many grams of the chemical will remain after 12 days? Round to the nearest hundredth of a gram. c. What is the "half-life" of this this substance? Round to the nearest day when no more than half remains. d. Calculate N'(2) and interpret the result in context.

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter31: Radioactivity And Nuclear Physics

Section: Chapter Questions

Problem 81PE: Unreasonable Results A physicist scatters (rays from a substance and sees evidence of a nucleus...

See similar textbooks

Similar questions

The ceramic glaze on a red-orange “Fiestaware” plate is U2O3and contains 50.0 grams of 238U, but very little 235U. (a) What is the activity of the plate? (b) Calculate the total energy that will be released by the 238U decay, (c) If energy is worth 12.0 cents per kWh , what is the monetary value of the energy emitted? (These brightly- colored ceramic plates went out of production some 30 years ago, but are still available as collectibles.)
Data from the appendices and the periodic table may be needed for these problems. Unreasonable Results (a) Repeat Exercise 31.57 but include the 0.0055% natural abundance of 234U with its 2.45105y halflife. (b) What is unreasonable about this result? (c) What assumption is responsible? (d) Where does the 234U come from if it is not primordial?
(a) Calculate the number of grams of deuterium in an 80.000L swimming pool, given deuterium is 0.0150% of natural hydrogen. (b) Find the energy released in joules if this deuterium is fused via the reaction 2H+2H3He+n. (c) Could the neutrons be used to create more energy? (d) Discuss the amount of this type of energy in a swimming pool as compared to that in, say, a gallon of gasoline, also taking into consideration that water is far more abundant.
The particles emitted in the decay of 3H (tritium) interact with matter to create light in a glow- in-the-dark exit sign. At the time of manufacture, such a sign contains 15.0 Ci of 3H. (a) What is the mass of the tritium? (b) What is its activity 5.00 y after manufacture?
Data from the appendices and the periodic table may be needed for these problems. (a) The 210Po source used in a physics laboratory is labeled as having an activity of 1.0 (Ci on the date it was prepared. A student measures the radioactivity of this source with a Geiger counter and observes 1500 counts per minute. She notices that the Source was prepared 120 days before her lab. What fraction of the decays is she observing with her apparatus? (b) Identify some of the reasons that only a fraction of the (s emitted are observed by the detector.
Data from the appendices and the periodic table may be needed for these problems. The ceramic glaze on a red-orange Fiestaware plate is U2O3 and contains 50.0 grams of 238U, but very little 235U. (a) What is the activity of the plate? (b) Calculate the total energy that will be released by the 238U decay. (c) If energy is worth 12.0 cents per kW (h, what is the monetary value of the energy emitted? (These plates went out of production some 30 years ago, but are still available as collectibles.)
Data from the appendices and the periodic table may be needed for these problems. There is more than one isotope of natural uranium. If a researcher isolates 1.00 mg of the relatively scarce 235U and finds this mass to have an activity of 80.0 Bq, what is its halflife in years?
World War II aircraft bad instruments with glowing radium-painted dials. The activity of one such instrument was 1.0105Bq when new. (a) What mass of 226Ra was present? (b) After some years, the phosphors on the dials deteriorated chemically, but the radium did not escape. What is the activity of this instrument 57.0 years after it was made?
Unreasonable Results A physicist scatters (rays from a substance and sees evidence of a nucleus 7.51013m in radius. (a) Find the atomic mass of such a nucleus. (b) What is unreasonable about this result? (c) What is unreasonable about the assumption?
(a) Calculate the energy released in the a decay of 238U. (b) What fraction of the mass at a single 238U is destroyed in the decay? The mass of 234Th is 234.043593 u. (c) Although the fractional mass loss is laws for a single nucleus, it is difficult to observe for an entire macroscopic sample of uranium. Why is this?
The naturally occurring radioactive isotope 232Th does not make good fission fuel, because it has an even number of neurons; however, it can be bred into a suitable fuel (much as 238U is bred into 239P). (a) What are Z and N for 232Th? (b) Write the reaction equation for neutron captured by 232Th and identify the nuclide AX produced in n+232ThAX+. (c) The product nucleus β decays, as does its daughter. Write me decay equations for each, and identify the final nucleus. (d) Conform that the final nucleus has an odd number of neutrons, making it a better fission fuel. (e) Look up the halflife of the final nucleus to see if it lives long enough to be a useful fuel.