June 2012 Chemistry Regents #69-71

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Question 51 Questions 52-55 Questions 56-59 Questions 60-62 Questions 63-65 Questions 66-68 Questions 69-71 Questions 72-75  Questions 76-78  Questions 79-81  Questions 82-85

 

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  Base your answers to questions 69 through 71  on the information below.

 

At standard pressure, hydrogen peroxide, H2O2, melts at -0.4C. boils at 151C, and is very soluble in water. A bottle of aqueous hydrogen peroxide, H2O(aq), purchased from a pharmacy has a pressure-releasing cap. Aqueous hydrogen peroxide decomposes at room temperature, as represented by the balanced equation below.

2H2O2(aq)==> 2H2O(l) + O2(g) + 196.0 kJ

69 State. in terms of both melting point and boiling point, why H2O2 is a liquid at room temperature. [1]

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room temperature is above the melting point and below the boiling point of H2O2

70 State evidence that indicates the decomposition of H2O2(aq) is exothermic. [1]

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Heat (energy) is a product of the reaction   or

more energy is released than absorbed

71 Explain why a hydrogen peroxide bottle needs a pressure-releasing cap. [I]

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As O2 is produced, the pressure inside the bottle increases and needs to be released

on to Questions 72-75

 

 

 

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

Question 51 Questions 52-55 Questions 56-59 Questions 60-62 Questions 63-65 Questions 66-68 Questions 69-71 Questions 72-75  Questions 76-78  Questions 79-81  Questions 82-85

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