January 2010 Chemistry Regents #51-52

Highlight to reveal answers and explanations

 

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

Questions 51-52 Questions 53-55 Questions 56-57 Questions 58-60 Questions 61-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-75 Questions 76-78 Questions 79-81 Questions 82-84

 

Other Regents Exams

Questions

Base your answers to questions 51 through 52 on the information below.

51 Based on Table G, determine the total mass of NH3 that must be dissolved in 200. grams of water to produce a saturated solution at 20.°C. [1]

HIGHLIGHT TO SEE THE ANSWER

112 g

(Using Table G, at 20C NH3 will dissolve 61g, however it is for 200g of water, so double this)u2O

52 Determine the total time that must elapse until only ¼ of an original sample of the radioisotope Rn-222 remains unchanged. [1]

HIGHLIGHT TO SEE THE ANSWER

ANSWER==>7.64 d.

1-->1/2-->1/4

(2 half lives x 3.82d)

On To Questions 53-55

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

Questions 51-52 Questions 53-55 Questions 56-57 Questions 58-60 Questions 61-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-75 Questions 76-78 Questions 79-81 Questions 82-84

 
Back to Regents Exams