June 2011 Chemistry Regents #83-85

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Base your answers to questions 83 through 85  on the information below.

Polonium-210 occurs naturally, but is scarce. Polonium-210 is primarily used in devices designed to eliminate static electricity in machinery. It is also used in brushes to removedust from camera lenses.

Polonium-210 can be created in the laboratory by bombarding bismuth-209 with neutrons to create bismuth-210. The bismuth-210 undergoes beta decay to produce polonium-210. Polonium-210 has a half-life of 138 days and undergoes alpha decay.

83.  State one beneficial use of Po-210. [1]

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from article-     Po-210 is used to eliminate static electricity in machinery     

or      removes dust from camera lenses

84. Complete the nuclear equation in your answer booklet for the decay of Po-210, by writing a notation for the missing product. [1]

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206 Pb
82

85. Determine the total mass of an original 28.0-milligram sample of Po-210 that remains unchanged after 414 days. [1]

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Answer =3.5mg

# of halflive=414d/138=3 halflives

28.0mg==>14.0==>7.0==>3.5mg

 

Regents Chemistry Exam June 2011 Scoring

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

Question 51 Questions 52-54 Questions 55-59 Questions 60-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-70 Questions 71-73 Questions 74-76 Questions 77-79 Questions 80-82 Questions 83-85

 
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