Radioactive Decay

The mass number of an isotope is

An alpha particle consists of __________ .

What is the daughter nuclide produced when Po-218 undergoes alpha decay?

In beta decay, the effective change in the nucleus is

What is the parent nuclide of the nuclear reaction that produces the daughter nuclide Hg-208 when undergoing beta decay?

Gamma rays are

The daughter nuclide of positron emission will differ from the parent nuclide by

What type of radioactive decay would result from an isotope with 40 protons and 80 neutrons?

Which of the following units takes into consideration the amount of damage to biological molecules?

A N/Z ratio close to 1 is most stable

Determine the age of a bone that has a decay rate of 3.80 dis/min ⋅ g C if the ratio of ¹²C:¹⁴C in living organisms has a decay rate of 15.3 dis/min ⋅ g C. (t_1/2 of ¹⁴C = 5730 years).

What is the balanced nuclear equation for the alpha decay of plutonium-238? (a) (b) (c) (d)

Write the balanced nuclear equation for the reaction represented by the diagram shown here. [Section 21.2]

The steps below show three of the steps in the radioactive decay chain for 23290Th. The half-life of each isotope is shown below the symbol of the isotope. (d) The next step in the decay chain is an alpha emission. What is the next isotope in the chain? [Sections 21.2 and 21.4]

The steps below show three of the steps in the radioactive decay chain for 23290Th. The half-life of each isotope is shown below the symbol of the isotope. (a) Identify the type of radioactive decay for each of the steps (i), (ii), and (iii). [Sections 21.2 and 21.4]

The accompanying graph illustrates the decay of 8842Mo, which decays via positron emission. (d) What is the product of the decay process? [Section 21.4]

Identify the true statement about nuclear power plants and nuclear weapons. (a) Nuclear power plants and nuclear weapons both use uranium enriched to about 90% U-235. (b) Nuclear power plants emit large amounts of CO2 just like coal burning power plants. (c) The United States produces less than 1% of its electrical power from nuclear energy. (d) A nuclear weapon explodes when two pieces of fission-able uranium-235 are pushed together to reach a critical mass.

Give the symbol for (c) gamma radiation.

Give the symbol for (b) an alpha particle.

Give the symbol for (c) a positron.

Give the symbol for (b) a beta particle.

Write balanced nuclear equations for the following processes: (c) krypton-76 undergoes positron emission.

Write balanced nuclear equations for the following transformations: (c) technicium-98 undergoes electron capture.

Write balanced nuclear equations for the following transformations: (a) bismuth-213 undergoes alpha decay.

Decay of which nucleus will lead to the following products: (a) bismuth-211 by beta decay?

Decay of which nucleus will lead to the following products: (b) chromium-50 by positron emission?

Decay of which nucleus will lead to the following products: (c) tantalum-179 by electron capture?

What particle is produced during the following decay processes: (c) iodine-122 decays to xenon-122?

Isotope A decays to isotope E through the following series of steps, in which the products of the individual decay events are themselves radioactive and undergo further decay until a stable nucleus is ultimately reached. Two kinds of processes are represented, one by the shorter arrows pointing right and the other by the longer arrows pointing left. (b) Identify and write the symbol for each isotope in the series:

Positron emission and electron capture both give a product nucleus whose atomic number is 1 less than the starting nucleus. Explain.

What is the difference between an a particle and a helium atom?

Why does beta emission raise the atomic number of the product while positron emission lowers. the atomic number?

Why does gamma emission not change the atomic number of the product?

Complete and balance the following nuclear equations by supplying the missing particle: (e) 5926Fe¡ 0-1e + ?

Complete and balance the following nuclear equations. (a)

Complete and balance the following nuclear equations. (b)

Complete and balance the following nuclear equations. (d)

Complete and balance the following nuclear equations. (a)

Complete and balance the following nuclear equations. (b)

Write a nuclear equation for the indicated decay of each nuclide. d. N-13 (positron emission)

Write a nuclear equation for the indicated decay of each nuclide. e. Cr-51 (electron capture)

Write a nuclear equation for the indicated decay of each nuclide. c. Pb-214 (beta)

Write a nuclear equation for the indicated decay of each nuclide. a. U-234 (alpha)

What particle is produced by the decay of thorium-214 to radium-210?

Write a nuclear equation for the indicated decay of each nuclide. e. Pd-103 (electron capture)

What particle is produced by the decay of uranium-239 to neptunium-239?

Write a partial decay series for Th-232 undergoing the sequential decays: a, b, b, a.

What particle is produced in each of the following decay reactions? (c)

What particle is produced in each of the following decay reactions? (b)

What particle is produced in each of the following decay reactions? (a)

Write a partial decay series for Rn-220 undergoing the sequential decays: a, a, b, b.

What particle is produced in each of the following decay reactions? (c)

What particle is produced in each of the following decay reactions? (b)

What particle is produced in each of the following decay reactions? (a)

Fill in the missing particles in each nuclear equation. c. 1911Ne ¡1910Ne + ____

Write balanced nuclear equations for the following processes. (b) Electron capture of 138Sm

Write balanced nuclear equations for the following processes. (c) Beta emission of 188W

Write balanced nuclear equations for the following processes. (a) Alpha emission of 162Re

Fill in the missing particles in each nuclear equation. d. 7535Br ¡ ____ + 0+1e

Fill in the missing particles in each nuclear equation. a. 24195Am ¡23793Np + ____

Fill in the missing particles in each nuclear equation. b. _____ ¡23392U + 0-1e

Fill in the missing particles in each nuclear equation. c. 23793 Np ¡ _____ +42He

Write balanced nuclear equations for the following processes. (b) Electron capture of 126Ba

Write balanced nuclear equations for the following processes. (a) Beta emission of 157Eu

Write balanced nuclear equations for the following processes. (c) Alpha emission of 146Sm

226Ac can decay by any of three different nuclear processes: a emission, b emission, or electron capture. Write a balanced nuclear equation for the decay of 226Ac by each process.

Americium-241, a radioisotope used in smoke detectors, decays by a series of 12 reactions involving sequential loss of a, a, b, a, a, b, a, a, a, b, a, and b particles. Identify each intermediate nucleus and the final stable product nucleus.

Radon-222 decays by a series of three a emissions and two b emissions. What is the final stable nucleus?

How many a particles and how many b particles are emitted in the 11-step decay of 235U into 207Pb?

Naturally occurring uranium-238 undergoes a radioactive decay series and emits 8 a particles and 6 b particles. What is the stable nucleus at the end of the series?

Why is it important that radioisotopes used as diagnostic tools in nuclear medicine produce gamma radiation when they decay? Why are alpha emitters not used as diagnostic tools?

Write the nuclear reaction for the neutron-induced fission of U-235 to form Xe-144 and Sr-90. How many neutrons are produced in the reaction?

Write the nuclear reaction for the neutron-induced fission of U-235 to produce Te-137 and Zr-97. How many neutrons are produced in the reaction?

Write the nuclear equation for the fusion of two H-2 atoms to form He-3 and one neutron.

Write the nuclear equation for the fusion of H-3 with H-1 to form He-4.

(c) What other substances are used as a moderator in nuclear reactor designs?

Complete and balance the nuclear equations for the following fission or fusion reactions: (a) 21H + 21H¡32He + _

Complete and balance the nuclear equations for the following fission reactions: (a) 23592U + 10n¡16062Sm + 7230Zn + _ 10n

The spent fuel elements from a fission reactor are much more intensely radioactive than the original fuel elements. (b) Given that only two or three neutrons are released per fission event and knowing that the nucleus undergoing fission has a neutron-to-proton ratio characteristic of a heavy nucleus, what sorts of decay would you expect to be dominant among the fission products?

Which are classified as ionizing radiation: X rays, alpha particles, microwaves from a cell phone, and gamma rays?

Radon-222 decays to a stable nucleus by a series of three alpha emissions and two beta emissions. What is the stable nucleus that is formed?

Chlorine has two stable nuclides, 35Cl and 37Cl. In contrast, 36Cl is a radioactive nuclide that decays by beta emission. (a) What is the product of decay of 36Cl?

The radioactive isotope 100Tc decays to form the stable iso-tope 100Mo. (a) There are two possible pathways for this decay. Write balanced equations for both.

Control rods in a nuclear reactor are often made of boron because it absorbs neutrons. Write the nuclear equation in which boron-10 absorbs a neutron to produce lithium-7 and an alpha particle.

What is the difference between uranium fuel rods in a nuclear power plant and uranium fuel for an atomic weapon?

Can fuel rods in a power plant be used to make an atomic weapon without further treatment? Explain.

What are the benefits of using fusion over fission as a source of nuclear energy? Why have fusion reactors not been developed yet?

Balance the following equations for the nuclear fission of 235U. (b)

Balance the following equations for the nuclear fission of 235U. (a)

The two most common isotopes of uranium are 235U and 238U. (d) 238U undergoes radioactive decay to 234Th. How many protons, electrons, and neutrons are gained or lost by the 238U atom during this process?

Indicate whether each of the following nuclides lies within the belt of stability in Figure 21.2: (a) neon-24. For any that do not, describe a nuclear decay process that would alter the neutron-to-proton ratio in the direction of increased stability. [Section 21.2]

In the sketch below, the red spheres represent protons and the gray spheres represent neutrons. (c) Based on its atomic number and mass number, do you think the product nucleus is stable or radioactive? [Section 21.3]

All the stable isotopes of boron, carbon, nitrogen, oxygen, and fluorine are shown in the accompanying chart (in red), along with their radioactive isotopes with t1>2 7 1 min (in blue). (b) Which radioactive isotopes are most likely to decay by beta emission? [Sections 21.2, 21.4, and 21.5]

Predict the type of radioactive decay process for the following radionuclides: (a) 85B.

Predict the type of radioactive decay process for the following radionuclides: (b) 6829Cu.

Each of the following nuclei undergoes either beta decay or positron emission. Predict the type of emission for each: (b) 8938Sr.

Each of the following nuclei undergoes either beta decay or positron emission. Predict the type of emission for each: (a) tritium, 31H.

Despite the similarities in the chemical reactivity of elements in the lanthanide series, their abundances in Earth’s crust vary by two orders of magnitude. This graph shows the relative abundance as a function of atomic number. Which of the following statements best explains the sawtooth variation across the series? (a) The elements with an odd atomic number lie above the belt of stability. (b) The elements with an odd atomic number lie below the belt of stability. (c) The elements with an even atomic number have a magic number of protons. (d) Pairs of protons have a special stability.

Which of the following nuclides would you expect to be radioactive: 5826Fe, 6027Co, 9241Nb, mercury-202, radium-226? Justify your choices.

Complete and balance the following nuclear equations by supplying the missing particle: (b) 21H + 32He¡42He + ?

Complete and balance the following nuclear equations by supplying the missing particle: (d) 12253I¡12254Xe + ?

Complete and balance the following nuclear equations by supplying the missing particle: (e) 23592U + 10n¡13554Xe + 2 10n + ?

Complete and balance the following nuclear equations by supplying the missing particle: (a) 147N + 42He¡? + 11H

Complete and balance the following nuclear equations by supplying the missing particle: (d) 5826Fe + 2 10n¡6027Co + ?

Determine whether or not each nuclide is likely to be stable. State your reasons. d. Te-124

Determine whether or not each nuclide is likely to be stable. State your reasons. c. Co-51

The first six elements of the first transition series have the following number of stable isotopes: Element Number of Stable Isotopes Sc 1 Ti 5 V 1 Cr 3 Mn 1 Fe 4 Explain why Sc, V, and Mn each have only one stable isotope while the other elements have several.

Of the two isotopes of tungsten, 160W and 185W, one decays by b emission and one decays by a emission. Which does which? Explain.

Of the two isotopes of iodine, 136I and 122I, one decays by b emission and one decays by positron emission. Which does which? Explain.

Predict a likely mode of decay for each unstable nuclide. b. Ru-90

Predict a likely mode of decay for each unstable nuclide. a. Mo-109

Of the two isotopes of iodine, 196Pb and 206Pb, one is nonra-dioactive and one decays by positron emission. Which does which? Explain.

Predict a likely mode of decay for each unstable nuclide. c. Fr-202

Predict a likely mode of decay for each unstable nuclide. a. Sb-132

Why do nuclei that are neutron-rich emit b particles? Why do nuclei that are neutron-poor emit a particles or positrons or undergo electron capture?

Which nuclide in each pair would you expect to have the longer half-life? a. Cs-149 or Cs-139

Rutherfordium-257 was synthesized by bombarding Cf-249 with C-12. Write the nuclear equation for this reaction.

Nuclear scientists have synthesized approximately 1600 nuclei not known in nature. More might be discovered with heavy-ion bombardment using high-energy particle accelerators. Complete and balance the following reactions, which involve heavy-ion bombardments: (b) 4020Ca + 24896Cm¡14762Sm + ?

In 2010, a team of scientists from Russia and the United States reported creation of the first atom of element 117, which is named tennessine, and whose symbol is Ts. The synthesis involved the collision of a target of 24997Bk with accelerated ions of an isotope which we will denote Q. The product atom, which we will call Z, immediately releases neutrons and forms 294117Ts: 24997Bk + Q¡Z¡294117Ts + 3 10n (b) Isotope Q is unusual in that it is very long-lived (its half-life is on the order of 1019 yr) in spite of having an unfavorable neutron-to-proton ratio (Figure 21.1). Can you propose a reason for its unusual stability?

Write the nuclear equation for the most likely mode of decay for each unstable nuclide. b. Ra-216

Write the nuclear equation for the most likely mode of decay for each unstable nuclide. a. Ru-114

Each of the following transmutations produces a radionuclide used in positron emission tomography (PET). (a) In equations (i) and (ii), identify the species signified as “X.” (i) 14N1p, a2X (ii) 18O1p, X218F (iii) 14N1d, n215O

The nuclide 247Es can be made by bombardment of 238U in a reaction that emits five neutrons. Identify the bombarding particle.

The nuclide 6Li reacts with 2H to form two identical particles. Identify the particles.

Give the products of the following nuclear reactions. (b)

Give the products of the following nuclear reactions. (a)

Element was prepared in 1982 by bombardment of atoms with atoms. Identify the other product that must have formed, and write a balanced nuclear equation assuming no other products were formed.

One of the new superheavy elements added to the periodic table in 2016 was synthesized when a beam of 48Ca ions was directed at a target of 243Am. (a) Write a balanced nuclear equation for the formation of this element. (b) What isotope is formed after the nuclide formed in the nuclear transmutation reaction in part (a) emits one alpha particle? (c) How many alpha particles were emitted to reach the isotope 268Db, the final decay product?

Fraud in science is rare but does happen occasionally. In 1999, the creation of three superheavy elements (one new) was claimed when 208Pb was bombarded with 86Kr. The claim was subsequently found to be fraudulent and was with-drawn. Identify the isotopes X, Y, and Z that were claimed.

The most abundant isotope of uranium, 238U, does not undergo fission. In a breeder reactor, however, a 238U atom captures a neutron and emits two b particles to make a fis-sionable isotope of plutonium, which can then be used as fuel in a nuclear reactor. Write a balanced nuclear equation.

Which of the following will undergo positron emission?

Which of the following correctly describes both nuclear fission and nuclear fusion?

In a linear accelerator, U-238 is bombarded by C-12 to form another element and six neutrons. What element is produced during this transmutation?

Determine the nuclear binding energy per nucleon (in MeV) of an He-4 nucleus that has a mass of 4.00150 amu.

Estimate the half-life of the isotope from the graph below.

How long will it take for 80% of a 1.20-mg sample of Rn-220 to decay? The half-life of Rn-220 is 55.6 s.

A sample of Th-219 requires 3.84 × 10⁻⁶ seconds to decay to 1.50 mg. What was the initial mass of the sample of Th-219? (t _1/2 for Th-219 = 1.05 × 10⁻⁶ s)

How many mg of a 3.50-mg sample of Tc-99 will remain after 4 half-lives have passed?

Fluorine-18 undergoes positron emission with a half-life of 1.10 x 10^2 minutes. If a patient is given a 250 mg dose for a PET scan, how long will it take for the amount of fluorine-18 to drop to 75 mg? (a) 56 minutes (b) 96 minutes (c) 132 minutes (d) 191 minutes

In a cave in Oregon, archaeologists found bones, plant remains, and fossilized feces. DNA remaining in the feces indi-cates their human origin but not their age. To date the remains, the decay rate was measured and found to be 2.71 disinte-grations/min per gram of carbon. Currently living organisms have a decay rate of 15.3 disintegrations/min per gram of carbon, and the half-life of 14C is 5715 years. How old are the remains? (a) 1460 years (b) 9900 years (c) 14300 years (d) 18600 years

The accompanying graph illustrates the decay of 8842Mo, which decays via positron emission. (b) What is the rate constant for the decay? [Section 21.4]

The accompanying graph illustrates the decay of 8842Mo, which decays via positron emission. (a) What is the halflife of the decay? [Section 21.4]

The accompanying graph illustrates the decay of 8842Mo, which decays via positron emission. (c) What fraction of the original sample of 8842Mo remains after 12 min? [Section 21.4]

Calculate the binding energy a uranium-235 nucleus in units of MeV/nucleon. The mass of an 235U atom is 235.043 929, the mass of a proton is 1.007 28, the mass of a neutron is 1.008 67, and the mass of an electron is 5.486 x 10^-4. (1 MeV = 1.60 x 10^-13 J) (a) 2.84 MeV/nucleon (b) 1.70 x 10^3 MeV/nucleon (c) 11.3 MeV/nucleon (d) 7.62 MeV/nucleon

How much energy in kJ/mol is released by the fission of uranium-235 to form barium-140 and krypton-93? The atomic masses are (a) 6.59 x 10^9 kJ/mol (b) 1.66 x 10^10 kJ/mol (c) 1.98 x 10^11 kJ/mol (d) 1.66 x 10^16 kJ/mol

Each statement that follows refers to a comparison between two radioisotopes, A and X. Indicate whether each of the following statements is true or false. (a) If the half-life for A is shorter than the half-life for X, A has a larger decay rate constant.

Some watch dials are coated with a phosphor, like ZnS, and a polymer in which some of the 1H atoms have been replaced by 3H atoms, tritium. The phosphor emits light when struck by the beta particle from the tritium decay, causing the dials to glow in the dark. The half-life of tritium is 12.3 yr. If the light given off is assumed to be directly proportional to the amount of tritium, by how much will a dial be dimmed in a watch that is 50 yr old?

It takes 4 h 39 min for a 2.00-mg sample of radium-230 to decay to 0.25 mg. What is the half-life of radium-230?

Cobalt-60 is a strong gamma emitter that has a half-life of 5.26 yr. The cobalt-60 in a radiotherapy unit must be replaced when its radioactivity falls to 75% of the original sample. If an original sample was purchased in June 2016, when will it be necessary to replace the cobalt-60?

The cloth shroud from around a mummy is found to have a 14C activity of 9.7 disintegrations per minute per gram of carbon as compared with living organisms that undergo 16.3 disintegrations per minute per gram of carbon. From the half-life for 14C decay, 5715 yr, calculate the age of the shroud.

Potassium-40 decays to argon-40 with a half-life of 1.27 * 109 yr. What is the age of a rock in which the mass ratio of 40Ar to 40K is 4.2?

One of the nuclides in spent nuclear fuel is U-235, an alpha emitter with a half-life of 703 million years. How long will it take for the amount of U-235 to reach 10.0% of its initial amount?

How much energy must be supplied to break a single aluminum-27 nucleus into separated protons and neutrons if an aluminum-27 atom has a mass of 26.9815386 amu? How much energy is required for 100.0 g of aluminum-27? (The mass of an electron is given on the inside back cover.)

A radioactive sample contains 1.55 g of an isotope with a halflife of 3.8 days. What mass of the isotope remains after 5.5 days?

A sample of F-18 has an initial decay rate of 1.5 * 105>s. How long will it take for the decay rate to fall to 2.5 * 103>s? (F-18 has a half-life of 1.83 hours.)

The half-life of indium-111, a radioisotope used in studying the distribution of white blood cells, is t1/2 = 2.805 days. What is the decay constant of 111In?

The atomic masses of nitrogen-14, titanium-48, and xenon-129 are 13.999234 amu, 47.935878 amu, and 128.904779 amu, respectively. For each isotope, calculate (a) the nuclear mass.

The decay constant of plutonium-239, a waste product from nuclear reactors, is 2.88 * 10-5 year - 1. What is the half-life of 239Pu?

Based on the following atomic mass values:1H, 1.00782 amu; 2H, 2.01410 amu; 3H, 3.01605 amu; 3He, 3.01603 amu; 4He, 4.00260 amu—and the mass of the neutron given in the text, calculate the energy released per mole in each of the following nuclear reactions, all of which are possibilities for a controlled fusion process: (b) 21H + 21H¡32He + 10n

Polonium-209, an a emitter, has a half-life of 102 years. How many alpha particles are emitted in 1.0 s from a 1.0 ng sample of 209Po?

A mammoth skeleton has a carbon-14 decay rate of 0.48 disintegration per minute per gram of carbon (0.48 dis>min # g C). When did the mammoth live? (Assume that living organisms have a carbon-14 decay rate of 15.3 dis>min # g C and that carbon- 14 has a half-life of 5715 yr.)

Iodine-131 is a convenient radioisotope to monitor thyroid activity in humans. It is a beta emitter with a half-life of 8.02 days. The thyroid is the only gland in the body that uses iodine. A person undergoing a test of thyroid activity drinks a solution of NaI, in which only a small fraction of the iodide is radioactive. (c) A normal thyroid will take up about 12% of the ingested iodide in a few hours. How long will it take for the radioactive iodide taken up and held by the thyroid to decay to 0.01% of the original amount?

A sample of 37Ar undergoes 8540 disintegrations/min initially but undergoes 6990 disintegrations/min after 10.0 days. What is the half-life of 37Ar in days?

Radioactive decay exhibits a first-order rate law, rate = -∆N/∆t = kN, where N denotes the number of radio-active nuclei present at time t. The half-life of strontium-90, a dangerous nuclear fission product, is 29 years. (a) What fraction of the strontium-90 remains after three half-lives?

Potassium ion, K+, is present in most foods and is an essen-tial nutrient in the human body. Potassium-40, however, which has a natural abundance of 0.0117%, is radioactive with t1/2 = 1.25 x 10^9 years. What is the decay constant of 40K? How many 40K+ ions are present in 1.00 g of KCl? How many disintegration/s does 1.00 g of KCl undergo?

The electronic systems on the New Horizons spacecraft, which launched on January 19, 2006, and reached its closest approach to Pluto on July 14, 2015, were powered by elec-tricity generated by heat. The heat came from the radioac-tive decay of 238Pu in the 11 kg of 238PuO2 fuel onboard. The generator provided 240 W when the spacecraft was launched. If the power output is directly proportional to the amount of 238Pu in the generator, what was the power output when the spacecraft reached Pluto? The half-life of 238Pu is 87.7 y.

If 1.0 g of matter is converted to energy, how much energy is formed?

A typical home uses approximately 1.0 * 103 kWh of energy per month. If the energy came from a nuclear reaction, what mass would have to be converted to energy per year to meet the energy needs of the home?

Calculate the mass defect and nuclear binding energy per nucleon of each nuclide. a. Li-7 (atomic mass = 7.016003 amu)

A laboratory rat is exposed to an alpha-radiation source whose activity is 14.3 mCi. (a) What is the activity of the radiation in disintegrations per second? In becquerels?

Calculate the quantity of energy produced per gram of U-235 (atomic mass = 235.043922 amu) for the neutron-induced fission of U-235 to form Xe-144 (atomic mass = 143.9385 amu) and Sr-90 (atomic mass = 89.907738 amu) (discussed in Problem 57).

Uranium-238 has a half-life of 4.47 * 109 years and decays through a series of events to yield lead-206. Estimate the age of a rock that contains 105 mmol of 238U and 33 mmol of 206Pb. Assume all the 206Pb is from the decay of 238U.

The age of an igneous rock that has solidified from magma can be found by analyzing the amount of 40K and 40Ar. Potassium-40 emits a positron to produce argon-40 and the half-life of 40K is 1.25 * 109 years. What is the age of a rock whose 40Ar/40K ratio is 1.42?

A 75-kg human has a dose of 32.8 rad of radiation. How much energy is absorbed by the person’s body? Compare this energy to the amount of energy absorbed by the person’s body if he or she jumped from a chair to the floor (assume that the chair is 0.50 m from the ground and that all of the energy from the fall is absorbed by the person).

Why does a given nucleus have less mass than the sum of its constituent protons and neutrons?

In an endothermic chemical reaction, do the products have more mass, less mass, or the same mass as the reactants? Explain.

Suppose a patient is given 1.55 mg of I-131, a beta emitter with a half-life of 8.0 days. Assuming that none of the I-131 is eliminated from the person’s body in the first 4.0 hours of treatment, what is the exposure (in Ci) during those first four hours?

Complete each nuclear equation and calculate the energy change (in J>mol of reactant) associated with each (Be-9 = 9.012182 amu, Bi-209 = 208.980384 amu, He-4 = 4.002603 amu, Li-6 = 6.015122 amu, Ni-64 = 63.927969 amu, Rg-272 = 272.1535 amu, Ta-179 = 178.94593 amu, and W-179 = 178.94707 amu). a. _____ +94Be ¡63Li + 42He

Calculate the mass defect (in g/mol) and the binding energy (in MeV/nucleon) for the following nuclei. Which of the two is more stable? (a) 50Cr (atomic mass = 49.94605) (b) 64Zn (atomic mass = 63.92915)

Calculate the mass defect (in g/mol) and the binding energy (in MeV/nucleon) for the following nuclei. Which of the two is more stable? (a) 7Li (atomic mass = 7.016004) (b) 39K (atomic mass = 38.963706)

Calculate the binding energy (in MeV/nucleon) for the following nuclei. (b) 84Kr (atomic mass = 83.91151)

Calculate the binding energy (in MeV/nucleon) for the following nuclei. (a)58Ni (atomic mass = 57.93535)

The nuclear masses of 7Be, 9Be, and 10Be are 7.0147, 9.0100, and 10.0113 amu, respectively. Which of these nuclei has the largest binding energy per nucleon?

What is the energy change ∆E (in kJ/mol) when an a particle is emitted from 174Ir? The atomic mass of 174Ir is 173.96666 the atomic mass of 170Re is 169.95804, and the atomic mass of a 4He atom is 4.00260.

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?

Find the binding energy in an atom of 3He, which has a mass of 3.016030 amu.

The radioactive isotope 100Tc decays to form the stable iso-tope 100Mo. (b) Only one of the pathways is observed. Calculate the energy released by both pathways, and explain why only one is observed. Relevant masses are: 100Tc = 99.907 657, 100Mo = 99.907 48, electron = 0.000 548 6.

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.

The half-life of 232Th is 1.4 * 1010 yr. Find the number of disintegrations per hour emitted by 1.0 mol of 232Th.

How much energy (in kJ/mol) is produced in the following fission reaction of plutonium-239?

How much energy (in kJ/mol) is released in the fusion reaction with 2H and 3He?

How much energy (in kJ/mol) is released in the fusion reaction of 1H and 2H atoms?

The nuclide 18F decays by both electron capture and b+ decay. Find the difference in the energy released by these two processes. The atomic masses are 18F = 18.000950 and 18O = 17.9991598.

A 255-gram laboratory rat is exposed to 23.2 rads. How many grays did the rat receive? How many joules were absorbed by the rat?

The maximum level of radon in drinking water is 4.0 pCi (4.0 x 10^-12Ci) per milliliter. (a) How many disintegrations occur per minute in 1 mL of water at the maximum radon level? (b) If the radioactive isotope is 222Rn(t1/2 = 3.8 days), how many 222Rn atoms are present in 1 mL of the water?

Nitrogen-16 is formed in the cooling water flowing through a hot reactor core in a nuclear power plant. It is formed when oxygen captures a neutron and then emits a b par-ticle. Determine the activity of 50.0 mg of 16N in units of Bq and Ci.

A proposed nuclear theory suggests that the relative abun-dances of the uranium isotopes 235U and 238U were approximately equal at the time they were formed. Today, the observed ratio of these isotopes is 7.25 x 10^-3. Give that the half-lives for radioactive decay are 7.04 x 19^8 are y for and 4.47 x 10^9 y for , calculate the age of the elements.

A small sample of wood from an archaeological site in Clo-vis, New Mexico, was burned in O2 and the CO2 produced was bubbled through a solution of Ba(OH)2 to produce a precipitation of BaCO3. When the BaCO3 was collected by filtration, a 1.000 g sample was found to have a radioactivity of 4.0 x 10^-5 Bq. The half-life of 14C is 5715 y, and living organisms have a radioactivity due to 14C if 15.3 disintegrations/min per gram of carbon. If the analysis was carried out in 1960, what is the date of the Clovis site?

Polonium-210, a naturally occurring radioisotope, is an alpha emitter, with t1/2=138 d. Assume that a sample fo 210Po with a mass of 0.700 mg was placed ina 250.0-mL flask, which was evacuated, sealed, and allowed to sit undisturbed. What would the pressure be inside the flask (in mmHg) at 20 degrees Celsius after 365 days if all the alpha particles emitted has become helium atoms?

Imagine that you have a 0.007 50 M aqueous MgCl2 solu-tion, prepared so that it contains a small amount of radio-active 28Mg. The half-life of 28Mg is 20.91 h, and the initial activity of the MgCl2 solution is 0.112 mCi>mL. Assume that 20.00 mL of this MgCl2 solution is added to 15.00 mL of 0.012 50 M aqueous Na2CO3 solution and that the resultant precipitate is then removed by filtration to yield a clear filtrate. After a long break to go for a run, you find that the activity of the filtrate measured 2.40 h after begin-ning the experiment is 0.029 mCi>mL. What are the molar concentrations of Mg2+ and CO32- in the filtrate, and what is the solubility product constant of MgCO3?