June 2017 Chemistry Regents #69-71

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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 54-57 Questions 58-60 Questions 61-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-76  Questions 77-80  Questions 81-82  Questions 83-85 

 

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Question 69-71

 

 

Base your answers to questions 69 through 71 on the information below and on your knowledge of chemistry. 

Ammonia, NH3(g), can be used as a substitute for fossil fuels in some internal combustion engines. The reaction between ammonia and oxygen in an engine is represented by the unbalanced equation below.

NH3(g) + O2(g) ==> N2(g) + H2O(g) + energy

69 Balance the equation in your answer booklet for the reaction of ammonia and oxygen, using the smallest whole-number coefficients. [1]

Answer-->  

_4_NH3(g) + _3_O2(g) ==> _2_N2(g) + _6_H2O(g) + energy

70 Show a numerical setup for calculating the mass, in grams, of a 4.2-mole sample of O. Use 32 g/mol as the gram-formula mass of O. [1]

Answer-->   4.2mol = X g/ (32g/mol)

or 4.2 x 32

 

71. Determine the new pressure of a 6.40-L sample of oxygen gas at 300. K and 100. kPa after the gas is compressed to 2.40 L at 900. K. [1]

Answer-->    800 kpa

PV/T =PV/T    )(100.kPa)(6.40L)/300K) =P ((2.40L)/900.K)

on to Questions 72-76

 

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 54-57 Questions 58-60 Questions 61-63 Questions 64-65 Questions 66-68 Questions 69-71 Questions 72-76  Questions 77-80  Questions 81-82  Questions 83-85 

 

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