The isotope 21 42 sc is unstable this is predictable

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14.The isotope2142Scis unstable. This is predictable becauseA.the number of neutrons is too large in relation to the number of protons.B.the number of neutrons is too small in relation to the number of protons.C.the atomic number is too large.D.the mass number is too large.E.Sc isotopes are all unstable.lOMoARcPSD|4064566
____15.A "rule of thumb" in the laboratory is that an isotope is completely decayed after 10 half-lives.What percent of the original activity would be left after 9 half-lives?
____16.Radium undergoes alpha decay. The product of this reaction also undergoes alpha decay. What isthe product of this second decay reaction?
____17.210Pbhas a half-life of 22.3 years and decays to produce206Hg. If you start with 7.50 g of210Pb,how many grams of206Hgwill you have after 17.5 years?lOMoARcPSD|4064566
____18.Several items were discovered in a cave on Samoa. The14C content was analyzed. The resultsshowed that the14C content was decaying at an average rate of 9.3 dpm/g C. When were theartifacts likely created?(The current14C/12C ratio is 15 dpm/g C and the half-life of14C is 5730 years)A.4700 yearsB.4900 yearsC.4300 yearsD.4200 yearsE.4000 years
____19.Calculate the energy released in the fission reaction235U+ n140Xe +94Sr +2n.(Assume235Uhas a nuclear mass of 234.993 amu,140Xeis 134.879 amu and94Sris 89.886 amu)
Form A, Page 6 of 17
____20.Fructose (C6H12O6) is oxidized by molecular oxygen to form carbon dioxide and water. How manymoles of O2are needed for each mole of fructose that is oxidized?lOMoARcPSD|4064566
____21.An iron ore, magnetite, contains only iron and oxygen. In refining 100.0 g of the ore, 77.5 g of ironare obtained. What is the empirical formula of the ore?
____22.If 112 g of KOH were used to prepare 500 mL of solution, what would the concentration be?A.1MB.2MC.3MD.4ME.6M
____23.The thermite reaction is used in welding applications and chemistry demonstrations because itreleases a tremendous amount of energy. Which of the following statements isnotcorrectregarding this reaction?8Al + 3Fe3O49Fe + 4Al2O3
Form A, Page 7 of 17
Form A, Page 8 of 17____

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Term
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Kerber
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