January 2016 Chemistry Regents #73-75

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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

Question 51-53 Questions 54-56
 Questions 57-61 Questions 62-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-82 Questions 83-85

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Questions

 

  Base your answers to questions 73 through 75 on the information below.

A laboratory technician is given the table below and a sample of one of the three substances listed in the table. The technician makes an aqueous solution with a portion of the sample. When a conductivity tester is lowered into the solution, the light bulb on the tester glows brightly. Another portion of the sample is placed in a heat-resistant container that is placed in an oven at 450.oC. The sample melts.

73 Identify the substance given to the technician. [1]

Answer==>sodium nitrate or NaNO3

74 State evidence that makes it necessary to use more than one property to identify the  substance given to the technician. [1]

Answer==> 2 substances are good conductors or 2 substances have melting points lower than 450.oC

75 Explain, in terms of ions, why an aqueous solution of potassium chromate conducts an  electric current. [1]

Answer==>The ions can move

 

on to Questions 76-78 

 

 
 

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

Question 51-53 Questions 54-56
 Questions 57-61 Questions 62-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-82 Questions 83-85

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