January 2015 Chemistry Regents #69-72

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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 54-55
 Questions 56-58 Questions 59-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-81 Questions 82-85

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Questions

 

  Base your answers to questions 69 through 72 on the information below.
 A student made a copper bracelet by hammering a small copper bar into the desired shape. The bracelet has a mass of 30.1 grams and was at a temperature of 21C in the classroom. After the student wore the bracelet, the bracelet reached a temperature of 33C. Later, the student removed the bracelet and placed it on a desk at home, where it cooled from 33C to 19C. The specific heat capacity of copper is 0.385 J/gK.

69 Explain, in terms of heat flow, the change in the temperature of the bracelet when the student wore the bracelet. [1]

Answer==> from the student to the bracelet

70 Determine the number of moles of copper in the bracelet. [1]

Answer==>0.474 mol

71 Show a numerical setup for calculating the amount of heat released by the bracelet as it cooled on the desk. [1]

Answer==>q =(30.1 g)(0.385 J/gK)(19C 33C)

72 Explain, in terms of chemical activity, why copper is a better choice than iron to make the bracelet. [1]

Answer==>Iron is more active

 

 
 

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 54-55
 Questions 56-58 Questions 59-61 Questions 62-63 Questions 64-65 Questions 66-68 Questions 69-72  Questions 73-75  Questions 76-78  Questions 79-81 Questions 82-85

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