Nuclear Chemistry or Radiochemistrv

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1 Nuclear Chemistry or Radiochemistrv -Know basic vocabulary -2 types of transmutations -4 nuclear decay emissions -Write nuclear decay reactions -Calculate y^ lives -know how nuclear powerplants work -Know about Chernobyl -Be able to complete the U-238 decay series Vocabulary Terms Responses Definitions Mass defect The difference between the actual mass of an atom and the sum of the masses of the isolated particles composing it Transmutation The conversion of one element into another; may be natural or artificial Binding energy The energy required to split the nucleus into separate nucleons Half-life The length of time necessary for one-half an amount of a radioactive nuclide to disintegrate Fission The splitting of an atomic nucleus into smaller fragments, accompanied by the release of neutrons and a large amount of energy Fusion A nuclear reaction in which small nuclei are combined to make a larger nucleus, accompanied by the release of a large amount of energy Alpha particle A helium nucleus, containing two protons and two neutrons Beta particle A fast moving electron emitted from certain radioactive nuclei; it is formed when a neutron decomposes Positron A particle that has the same mass as an electron but has a positive charge Radioactive decay The process in which an unstable nucleus loses energy by emitting radiation Gamma rays A quantum of energy of very high frequency and very short wavelength Geiger counter A gas-filled metal tube used to detect the presence of beta radiation Radioisotope Isotopes that have unstable nuclei and undergo radioactive decay Band of stability The location of stable nuclei on a neutron-vs.-proton plot Nucleon A particle found in the nucleus of an atom; a proton or a neutron Nuclide An atom of a specific energy with a specified number of protons and a specified number of neutrons in its nucleus Ionizing radiation Radiation which has enough energy to produce ions by knocking electrons off some of the atoms it strikes Chain reaction A self-sustaining fission process caused by the production of neutrons that proceed to split other nuclei Radiotracer A radioactive nuclide, introduced into an organism for diagnostic purposes, whose pathway can be traced by monitoring its radioactivity

2 Nuclides (I) Nuclide Atomic# Mass# #Protons #Electrons #Neutrons Hyphen notation Helium-4 2 Nuclear notation Carbon - 14 Boron Silicon Copper -63 Arsenic Bromine Gold Radon Uranium Neon Copper Lithium- 6 3

3 Name i^jl ^'^ Types of Nuclear Decay ^... A nuclear reaction is a reaction that affects the of an atom.... A transmutation is a change in the identity of a nucleus as a result of a change in the number of its.... Radioactive decay is the spontaneous disintegration of a nucleus into a slightly lighter nucleus, accompanied by emission of,, or both. Nuclear change or decay is an process. The stability of a nuclide partly depends on the relative number of and it contains. In some cases, having too many neutrons is the cause of the. Stable nuclides are recognized experimentally because they do not change. Unstable nuclides in order to reach stability. Changing to a stable nuclide may involve one or more decays. In nuclear decay, the initial nucleus is called the, and the nev^ nucleus that results is called the. Nuclear equations representing a nuclear reaction are balanced when the sum of the atomic numbers on the right is equal to the on the left. Sums of the numbers on the right and left sides must be equal also. Nuclear Decay Organizer and Nuclear Equation Practice Alpha Particle Emission Beta Particle Emission Positron Particle Emission Symbol 2He or a > or_?^.ip Gamma Ray Emission How It changes the nucleus......decreases the mass number by 4...Converts a neutron into a proton...converts a proton into a neutron....no change to the nucleus... Decreases the atomic # by 2...Increases atomic # by 1... Atomic # decreases by 1; mass # stays same Examples of Nuclear Decay Processes a emission p emission p * emission ^llu the + ^tth 1. \Nr\te an equation to represent the decay of radium-226 by a emission and bismuth-209 by 3^ emission. 2. The products from a nuclear reaction are an a particle and polonium-218. Identify the parent nuclide and write equation. 3. Write equations for the decay of and radium-224 by a emission. 4. Write equations for the decay of cobalt-60 and calcium-39 by P emission. 5. Write an equation for the decay of copper-64 and nitrogen-12 by p'^emission. 6. Fill in the correct symbol to complete each equation. a) ^^2U ^? +2^6 b) mm ^? _?e c) 'llra -> 'llrn +? d) f.k ^ t ]Ca +? 7. Write an equation for the decay of polonium-218 by a emission. 8. Write an equation for the decay of carbon-14 by p" emission. Then by P * emission.

4 Table O Symbols Used in Nuclear Chemistry Name Notation Symbol alpha particle llie or a a beta particle _','< r gamma radiation?,y Y neutron n proton TI <>,- {p P positron 1^"

5 Name Per Nuclear Decay Using a periodic table, fill in the blanks to complete the following nuclear equations. Then, identify which type(s) of decay particles were produced. Standard: Students know the three most common forms of radioactive decay (alpha, beta, and gamma) and know how the nucleus changes in each type of decay. 05 < > CD CD CD 6^ ^ + 7iV 'i'c + ; / / ^ + V

6 Nuclear Chemistry Worksheet Using your knowledge of nuclear chemistry, write the equations for the following processes: 1) The alpha decay of radon-198 2) The beta decay of uranium-237 3) Positron emission from silicon-26 4) Sodium-22 undergoes electron capture 5) What is the difference between nuclear fusion and nuclear fission? 6) What is a "mass defect" and why is it important? 7) Name three uses for nuclear reactions. For chemistry help, visit www. chem fiesta, com 2003 Cavalcade Publishing- All Rights Reserved

7 Nuclear Chemistry Worksheet - Solutions Using your knowledge of nuclear chemistry, write the equations for the following processes: 1) The alpha decay of radon-198 2) The beta decay of uranium ) Positron emission from silicon-26 4) Sodium-22 undergoes electron capture 5) What is the difference between nuclear fusion and nuclear fission? In nuclear fusion, small nuclei are combined to form a larger nucleus " this process releases a very large amount of energy, and is the main source of energy in the sun. In nuclear fission, large nuclei break apart to form smaller ones, releasing a large amount of energy. Fission is used in nuclear power plants to generate energy. 6) What is a "mass defect" and why is it important? "Mass defect" refers to the difference between the mass of the nucleons (protons + neutrons) in a nucleus when weighed separately and the mass of the nucleus when it's put together. This difference is important because this missing mass is converted to energy using E=mc^ that's used to hold the nucleus together. 7) Name three uses for nuclear reactions. Nuclear weapons Medicine Nuclear power generation For chemistry help, visit www. chemfiesta. com 2003 Cavalcade Publishing- All Rights Reserved

8 Name pd 2009 Half-Life In a sample of radioactive nuclides, the decay of an individual nuclide is a event. It is impossible to predict which nucleus will be the next one to undergo a nuclear change. How, then, do you make sense out of things that cannot be predicted on an individual basis? One approach is to predict change for a given amount of a very large number of nuclei for example, one half. Scientists commonly discuss radioactive decay in terms of half-life. The it tal<es for one half of the parent nuclides in a radioactive sample to decay is known as its half-life. The half-life of fluorine-21 is approximately five seconds. If a sample of fluorine-21 contains one million atoms, then of the nuclei will decay within five seconds. Within another five seconds, additional nuclei (one half of those remaining) will decay, and so on. Many radioactive nuclei have much longer half-lives. A sample of one million nuclei of strontium-90 will decay much more slowly because the half-life of strontium-90 is about 29 years. Half -lives may be used calculate the fraction of parent nuclides that remain after a certain amount of time. Helpful Hints!! (Use your y" button or x^); n = total time / Vz life time; n = # of >i lives that have occurred; mass remaining = mass x Vz Sample calculation: Fluorine-21 has a half-life of approximately 5 seconds. What fraction of the original nuclei would remain after 1 minute? If you began with 42 grams of fluorine, how many grams of fluorine would remain? 9. lodine-131 has a half-life of 8 days. What fraction of the original sample would remain at the end of 32 days? 10. The half-life of chromium-51 is 28 days. If a sample contained 510 grams, how much chromium would remain after 56 days? How much would remain after 1 year? 11. The half-life of iodine-125 is 60 days. What fraction of iiodine-125 would be left after 350 days? 12. Titanium-51 decays by P " emission with a half-life of 6 minutes. What fraction of titanium would remain after 1 h? 13. A medical institution requests 1 gram of bismuth-214, which has a half-life of 20 min. How many grams of bismuth-214 must be prepared and shipped, if the shipping time is exactly 2 h? 14. What fraction of radioactive strontium-90, formed in the last atmospheric nuclear-bomb test in 1963, will be present in the environment in the year 2050? The half-life of strontium-90 is 29 years? 15. The half-life of phosphorus-30 is 2.5 min. What fraction of phosphorus-30 would remain after 10 min? 16. Chromium-48 decays by P^emission. After 6 half-lives, what fraction of the original nuclei would remain?

9 Name WS Half-life 2 The Half-Life of Radon-226 is approximately 4 days. On the grid below, plot the amount of Radon-226 left after each 4 day time period when you start with a 48g sample of Radon i i \ "i \ i \ 1 j 1 i! 1 :. j... ; i \ i j 1 i 1! 1 1 i 1 i 1 r 1 1 ; 1! j : 1 ;. : :. 1 : i i ; i i \ Questions 1. How many grams of radon would be present after 4 days? 2. How many grams of radon would be present after 12 days? 3. How many grams of radon would be present after 24 days? 4. If 8 g of radon are left, what is the time elapsed? 5. How many grams of radon would be present after 6 days?

10 Name WS Decay Series of U Complete the table using the decay series of U CO ^0? atomic number 2. Complete the reactions and mark the graph above with the nuclide that is formed U

11 u a Th Pa u a Po a Rn a Ra a th a Pb Bi Po a Pb 6 stable ^^^Pb 82 a Po 83

12 Table K Common Acids Table N Selected Radioisotopes HCl(aq) Formula HN02(aq) HN03(aq) H2S03(aq) HgSO^lati) H3P04(aq) H2C03(aq) or C02(aq) CH3COOH(aq) or HC2H302(aq) Name hydrochloric acid nitrous acid nitric acid sulfurous acid sulfuric acid phosphoric acid carbonic acid ethanoic acid (acetic acid) Nuclide Half-Life Decay Mode Nuclide Name d r gold c 5715 y carbon-14 -Ca 182 ms calcium y r cobalt-60 13'CS 30.2 y p- cesium min iron-53 22UF, 27.4 s a francium V r hydrogen d r iodine s potassium-37 42K h potassium-42 Table L Common Bases V r kiypton-85 16^ s (3- nitrogen-16 Formula NaOH(aq) KOH(aq) Ca(OH)2(aq) NH3(aq) Name sodium hydroxide potassium hydroxide calcium hydroxide aqueous ammonia l9ne s (3^ neon-19 32p d 3- phosphorus p^ X 10^ y a plutonium y a radium d a radon s, 29.1 y P- strontium-90 Table M Common Acid-Base Indicators Indicator Approximate ph Range for Color Change Color Change methyl orange red to yellow 2.13 X lo^y (3- technetium Th 1.40 X 10^0 y a thorium u X 10\ a uranium u 7.04 X 10''^ y a uranium Su 4.47 X lo'^ y a uranium-238 Source: CRC Handbook of Chemistry and Physics, 91^* ed., , CRC Press bromthymol blue yellow to blue phenolphthalein 8-9 colorless to pink litmus red to blue bromcresol green vellow to blue thymol blue yellow to blue Source: The Merck Index, 14'^ ed., 2006, Merck Publishing Group Reference Tables for Physical Setting/Chemistry Edition

Chapter 22 - Nuclear Chemistry

Chapter 22 - Nuclear Chemistry Chapter - Nuclear Chemistry - The Nucleus I. Introduction A. Nucleons. Neutrons and protons B. Nuclides. Atoms identified by the number of protons and neutrons in the nucleus 8 a. radium-8 or 88 Ra II.