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Problem 78b,c
Complete each nuclear equation and calculate the energy change (in J/mol of reactant) associated with each (Al-27 = 26.981538 amu, Am-241 = 241.056822 amu, He-4 = 4.002603 amu, Np-237 = 237.048166 amu, P-30 = 29.981801 amu, S-32 = 31.972071 amu, and Si-29 = 28.976495 amu).
b. 3216S + ______ → 2914Si + 42He
c. 24195Am → 23793Np + _____
Problem 79a,c,d
Write the nuclear equation for the most likely mode of decay for each unstable nuclide. a. Ru-114 c. Zn-58 d. Ne-31
Problem 79b
Write the nuclear equation for the most likely mode of decay for each unstable nuclide. b. Ra-216
Problem 80
Write the nuclear equation for the most likely mode of decay for each unstable nuclide. a. Kr-74 b. Th-221 c. Ar-44 d. Nb-85
- Bismuth-210 is a beta emitter with a half-life of 5.0 days. If a sample contains 1.2 g of Bi-210 (atomic mass = 209.984105 amu), how many beta emissions occur in 13.5 days? If a person’s body intercepts 5.5% of those emissions, what amount of radiation (in Ci) is the person exposed to?
Problem 81
- Polonium-218 is an alpha emitter with a half-life of 3.0 minutes. If a sample contains 55 mg of Po-218 (atomic mass = 218.008965 amu), how many alpha emissions occur in 25.0 minutes? If the polonium is ingested by a person, to what amount of radiation (in Ci) is the person exposed?
Problem 82
Problem 83
Radium-226 (atomic mass = 226.025402 amu) decays to radon-222 (a radioactive gas) with a half-life of 1.6⨉103 years. What volume of radon gas (at 25.0 °C and 1.0 atm) does 25.0 g of radium produce in 5.0 days? (Report your answer to two significant digits.)
- In one of the neutron-induced fission reactions of U-235 (atomic mass = 235.043922 amu), the products are Ba-140 and Kr-93 (a radioactive gas). What volume of Kr-93 (at 25.0 °C and 1.0 atm) is produced when 1.00 g of U-235 undergoes this fission reaction?
Problem 84
- When a positron and an electron annihilate one another, the resulting mass is completely converted to energy. Calculate the energy associated with this process in kJ/mol.
Problem 85
Problem 86
A typical nuclear reactor produces about 1.0 MW of power per day. What is the minimum rate of mass loss required to produce this much energy?
Problem 87
Find the binding energy in an atom of 3He, which has a mass of 3.016030 amu.
- The overall hydrogen burning reaction in stars can be represented as the conversion of four protons to one alpha particle. Use the data for the mass of H-1 and He-4 to calculate the energy released by this process.
Problem 88
Problem 89
The nuclide 247Es can be made by bombardment of 238U in a reaction that emits five neutrons. Identify the bombarding particle.
Problem 90
The nuclide 6Li reacts with 2H to form two identical particles. Identify the particles.
Problem 91
The half-life of 238U is 4.5⨉109 yr. A sample of rock of mass 1.6 g produces 29 dis/s. Assuming all the radioactivity is due to 238U, find the percent by mass of 238U in the rock.
Problem 92
The half-life of 232Th is 1.4⨉1010 yr. Find the number of disintegrations per hour emitted by 1.0 mol of 232Th.
- A 1.50-L gas sample at 745 mm Hg and 25.0 °C contains 3.55% radon-220 by volume. Radon-220 is an alpha emitter with a half-life of 55.6 s. How many alpha particles are emitted by the gas sample in 5.00 minutes?
Problem 93
Problem 94
A 228-mL sample of an aqueous solution contains 2.35% MgCl2 by mass. Exactly one-half of the magnesium ions are Mg-28, a beta emitter with a half-life of 21 hours. What is the decay rate of Mg-28 in the solution after 4.00 days? (Assume a density of 1.02 g/mL for the solution.)
- When a positron and an electron collide and annihilate each other, two photons of equal energy are produced. What is the wavelength of these photons?
Problem 95
Problem 96
The half-life of 235U, an alpha emitter, is 7.1⨉108 years. Calculate the number of alpha particles emitted by 1.0 mg of this nuclide in 1.0 minute.
Problem 97
Given that the energy released in the fusion of two deuterons to a 3He and a neutron is 3.3 MeV, and in the fusion to tritium and a proton it is 4.0 MeV, calculate the energy change for the process 3He + 1n → 3H + 1p. Suggest an explanation for why this process occurs at much lower temperatures than either of the first two.
Problem 98
The nuclide 18F decays by both electron capture and β+ decay. Find the difference in the energy released by these two processes. The atomic masses are 18F = 18.000950 and 18O = 17.9991598.