Chapter 28 Nuclear Chemistry Guided Reading Answers

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Chapter 21 Nuclear Chemistry PowerPoint Presentation

Chapter 21 Nuclear Chemistry

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Affiliate 21 Nuclear Chemistry

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1. Chemistry, The Central Science, tenth edition Theodore L. Chocolate-brown; H. Eugene LeMay, Jr.; and Bruce East. Bursten Chapter 21Nuclear Chemistry John D. Bookstaver St. Charles Customs College St. Peters, MO  2006, Prentice Hall, Inc.

2. January 28 • Nuclear chemical science • HW • one,xi, 13, 29, 33, 35, 41 for tomorrow

3. DO NOWREACTION OF THE Mean solar day • Hydrochloric acid is added to a solution of lithium sulfide. • Write the molecular equation and then the net ionic equation

4. The Nucleus • Call back that the nucleus is comprised of the two nucleons, protons and neutrons. • The number of protons is the diminutive number. • The number of protons and neutrons together is finer the mass of the atom.

5. Isotopes • Not all atoms of the same element take the same mass due to dissimilar numbers of neutrons in those atoms. • There are three naturally occurring isotopes of uranium: • Uranium-234 • Uranium-235 • Uranium-238

7. Radioactivity • It is not uncommon for some nuclides of an element to be unstable, or radioactive. • We refer to these equally radionuclides. • At that place are several ways radionuclides tin can decay into a unlike nuclide.

8. Types ofRadioactive Decay

10. SeparationAlphaBetaGamma.MOV Separation of Radiation

14. Nuclear Reactions • The chemical properties of the nucleus are contained of the state of chemical combination of the cantlet. • In writing nuclear equations we are not concerned with the chemical form of the atom in which the nucleus resides. • It makes no difference if the atom is as an element or a compound. • Mass and charges MUST Be Balanced!!!

15. 238 92 234 90 four 2 4 2 He U Thursday He +  Alpha Decay: Loss of an -particle (a helium nucleus)

16. Alpha Decay • Mass changes by 4 • The remaining fragment has 2 less protons • Alpha radiation is the less penetrating of all the nuclear radiation (information technology is the most massive one!)

17. 131 53 131 54 0 −i 0 −1 0 −1 e I Xe due east  +  or Beta Decay: Loss of a -particle (a high energy electron)

18. Beta Decay • Involves the conversion of a neutron in the nucleus into a proton and an electron. • Beta radiation has loftier energies, can travel upwards to 300 cm in air. • Tin penetrate the pare

19. Beta decay • Write the reaction of decay for C-14

20. 0 0  Gamma Emission: Loss of a -ray (loftier-energy radiation that almost ever accompanies the loss of a nuclear particle)

21. eleven 6 xi 5 0 1 0 1 e + C B e +  Positron Emission: Loss of a positron ( particle with aforementioned mass, but reverse charge than an electron)

22. Positron emission • Involves the conversion of a proton to a neutron emitting a positron. • The diminutive number decreases by one, mass number remains the same.

23. 0 −1 i one 1 0 p e n +  Electron Capture (K-Capture) Capture by the nucleus of an electron from the electron deject surrounding the nucleus. • Equally a effect, a proton is transformed into a neutron.

24. 81 37 81 36 Rb Kr  Electron capture • Rb-81 • Annotation that the electron goes in the side of the reactants. Electron gets consumed.

25. Patterns of nuclear Stability • Any element with more than ane proton ( all but hydrogen) will have repulsions between the protons in the nucleus. • A strong nuclear strength helps keep the nucleus from flying apart.

26. Neutron-Proton Ratios • Neutrons play a cardinal office stabilizing the nucleus. • The ratio of neutrons to protons is key to determine the stability of a nucleus .

27. Neutron-Proton Ratios As nuclei get larger, it takes a greater number of neutrons to stabilize the nucleus.

28. Neutron-Proton Ratios For smaller nuclei (Z  20) stable nuclei have a neutron-to-proton ratio close to 1:1.

29. Stable Nuclei The shaded region in the figure shows what nuclides would be stable, the so-called chugalug of stability.

30. Stable Nuclei • Nuclei above this belt have too many neutrons. • They tend to disuse past emitting beta particles. ( neutron becomes proton )

31. In a higher place the belt of stabilityBeta particle emission • Besides many neutrons. The nucleus emits Beta particles, decreasing the neutrons and increasing the number of protons.

32. Stable Nuclei • Nuclei below the belt accept besides many protons. • They tend to become more stable by positron emission or electron capture (both lower the number of protons)

33. Stable Nuclei • Elements with low atomic number are stable if # proton = # neutrons • There are no stable nuclei with an atomic number greater than 83. • These nuclei tend to decay past alpha emission.

34. Below the stability beltIncrease the number of neutrons (past decreasing # protons) • Positron emission more mutual in lighter nuclei. • Electron capture mutual for heavier nuclei.

36. Radioactive Series • Big radioactive nuclei cannot stabilize by undergoing only ane nuclear transformation. • They undergo a serial of decays until they grade a stable nuclide (often a nuclide of lead).

37. Predicting modes of nuclear decay C-14 Xe-118 Pu-239 In-120

38. beta decay • Positron emission or electron capture • Alpha disuse (too heavy, loses mass) • Beta decay (ratio too low, gains protons)

39. MAGIC NUMBERS2, 8, twenty, 28, 50, or 82 Nuclei with 2, 8, twenty, 28, 50, or 82 protons or two, 8, 20, 28, 50, 82, or 126 neutrons tend to be more stable than nuclides with a unlike number of nucleons.

40. Some Trends Nuclei with an fifty-fifty number of protons and neutrons tend to be more stable than nuclides that have odd numbers of these nucleons.

41. Shell model of the nucleus • Nucleons are described a residing in shells like the shells for electrons. • The numbers 2,viii,18,36,54,86 correspond to closed shells in nuclei. • Evidence suggests that pair of protons and pairs of neutrons have special stability

42. Transmutations • To change one chemical element into some other. • Only possible in nuclear reactions never in a chemic reaction. • In social club to modify the nucleus huge amount of free energy are involved. • These reactions are carried in particle accelerators or in nuclear reactors

43. Nuclear transmutations • Alpha particles have to move very fast to overcame electrostatic repulsions betwixt them and the nucleus. • Particle accelerators or smashers are used. They use magnetic fields to accelerate the particles.

44. Particle Accelerators(only for charged particles!) These particle accelerators are enormous, having circular tracks with radii that are miles long.

45. Cyclotron Nuclear transformations can be induced past accelerating a particle and colliding it with the nuclide.

46. Neutrons • Can non be accelerated. They do not need information technology either (no charge!). • Neutrons are products of natural disuse, natural radioactive materials or are expelled of an artificial transmutation. • Some neutron capture reactions are carried out in nuclear reactors where nuclei tin exist bombarded with neutrons.

47. Representing bogus nuclear transmutations • 14N + 4He  7O + 1H Target nucleus ( bombarding particle, ejected particle ) product nucleus • 14N (a, p) 17O • Write the balanced nuclear equations summarized every bit followed: • sixteen O ( p, a) North • 27Al (n, a)24 Na

48. Measuring Radioactivity • Ane tin can use a device like this Geiger counter to measure out the amount of activity present in a radioactive sample. • The ionizing radiation creates ions, which behave a current that is detected by the instrument.

49. Mass defect • The mass of the nucleus is always smaller than the masses of the individual particles added upwardly. • The departure is the mass defect. • That small corporeality interpret to huge amounts of free energy E = (grand) c2 • That energy is the Binding energy of the nucleus, and is the energy needed to dissever the nucleus.

50. Energy in Nuclear Reactions For example, the mass change for the decay of 1 mol of uranium-238 is −0.0046 k. The modify in energy, Due east, is so Eastward = (m) c2 E= (−iv.6  x−6 kg)(3.00  108 m/s)2 Due east= −4.i  1011 J This amount is 50,000 times greater than the combustion of ane mol of CH4

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