General Chemistry Chapters 19, 21, 22 Essay

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HOMEWORK EXAM 3: Chapter 19: The half life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later? Answer 0.166 0.125 0.062 here 0.015 Which relation is not correct? Answer 11p = 11H = proton 0-1e = 0-1β = electron here +10e = +10β= positron 10n = neutron As a result of beta decay, the product nucleus is Answer one atomic number lower than the original element. two atomic number higher than the original element. here one atomic number higher than the original element. two atomic number lower than the original element. What is X for the nuclear reaction: 21284Po à 20882Pb + X Answer 42p 1-1β…show more content…
T Enhancing the ability of a semiconductor to conduct electricity by adding small amount of certain impurities to the element. Enhancing the ability of a semiconductor to conduct electricity by adding significant amount of certain impurities to the element. What is the correct sequence of the recovery ofa metal from its ore? Answer T preparation of the ore --> production of the metal --> purification of the metal preparation of the ore --> purificaiton of the metal --> production of the metal purification of the metal --> preparation of the ore --> production of the metal production of the metal --> purification of the metal --> preparaiton of the ore Which one of the following is the best electric conductor? Answer T Mg C Si P CHAPTER 22 Which aqueous solution of oxoacids of the halogens is the strongest acid? Answer HClO HClO2 HClO3 Here check HClO4 Which one is not metal? Answer Li Be Here (mettaloid) check B Sn Which oxide is basic? Answer SiO2 SO3 Here (alkaline earth met)? MgO Cl2O7 Which is not an isotope of hydrogen? Answer hydrogen tritium deuterium Here check dextrium Which one is in mismatch? Answer Ammonia - NH3 Nitrous oxide - N2O Nitric oxide - NO Nitrous acid check HNO2 - nitiric acid Which aqueous solution of hydrogen halide is the weakest acid? Answer
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