January 2014 Chemistry Regents #81-85

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Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions 51-54 Questions 55-57 Questions 58-61 Questions 62-63 Questions 64-65 Questions 66-70

Questions 71-75 Questions 76-77 Questions 78-81 Questions 82-85

 

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Questions

 

  Base your answers to questions 81 through 85 on the information below.

Iodine has many isotopes, but only iodine-127 is stable and is found in nature. One
radioactive iodine isotope, I-108, decays by alpha particle emission. Iodine-131 is also  radioactive and has many important medical uses.


82 Determine the number of neutrons in an atom of I-127. [1]

Answer-->  74


83 Explain, in terms of protons and neutrons, why I-127 and I-131 are different isotopes of iodine. [1]

Answer-->  same atomic number (protons) but different numbers of neutrons


84 Complete the equation in your answer booklet for the nuclear decay of I-108. [1]

Link to ANSWER


85 Determine the total time required for an 80.0-gram sampleof I-131 to decay until only 1.25 grams of the sample remains unchanged. [1]

Answer-->  48days

 

 

 
 

Questions 1-10 Questions 11-20 Questions 21-30 Questions 31-40 Questions 41-50

Questions 51-54 Questions 55-57 Questions 58-61 Questions 62-63 Questions 64-65 Questions 66-70

Questions 71-75 Questions 76-77 Questions 78-81 Questions 82-85

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