June 2015 Chemistry Regents #76-79

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Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Questions 51-53 Questions 54-56 Questions 57-59 Questions 60-61 Questions 62-65 Questions 66-68 Questions 69-72 Questions 73-75  Questions 76-79  Questions 80-82  Questions 83-85

 

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Question 76-79

 

 

Base your answers to questions 76 through 79 on the information below and on your knowledge of chemistry.

 A sample of seawater is analyzed. The table below gives the concentration of some ions in the sample.

76 Write the chemical formula of one compound formed by the combination of K+ ions with one of theses ions as the water completely evaporates from the seawater sample. [1]

Answer-->  either KCl  or K2SO4   

(no charges allowed in the formula)

77  Determine the number of moles of the SO42- ion in a 1400.-liter sample of the seawater.

Answer-->39 moles

Work not necessary  0.028M= x moles/1400L

78 Compare the radius of the Mg2+ ion to the radius of an Mg atom.

Answer-->Mg atom is larger than the ion

or    the Mg2+ is smaller    (it did not ask why?)

79. Using the key in your answer booklet, draw two water molecules in the box, showing the orientation of each water molecule towards the calcium ion. [1]

Link to answer 79

 

on to Questions 80-82

 

 

Questions 1-5 Questions 6-10 Questions 11-15 Questions 16-20 Questions 21-25 Questions 26-30 Questions 31-35 Questions 36-40 Questions 41-45 Questions 46-50

Questions 51-53 Questions 54-56 Questions 57-59 Questions 60-61 Questions 62-65 Questions 66-68 Questions 69-72 Questions 73-75  Questions 76-79  Questions 80-82  Questions 83-85

 

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