January 2009 Chemistry Regents #51-53

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 

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Questions

Base your answers to questions 51 through 53 on the information below.

51 In the box in your answer booklet, draw a Lewis electron-dot diagram for an atom of boron. [1]

 Link TO SEE THE ANSWER 51

52 Explain, in terms of atomic structure, why the noble gas neon is an unreactive element. [1]

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Neon has eight valence electrons.

Neon has atoms with a complete outer shell of electrons.

Neon has a complete octet.

53 Given the equation representing a reaction at equilibrium:

N2(g) + 3H2(g) <==>2NH3(g)

Explain, in terms of collision theory, why the rate of the forward reaction decreases when the concentration of N2(g) is decreased. [1]

HIGHLIGHT TO SEE THE ANSWER

fewer effective collisions

The rate of the forward reaction decreases because there are fewer N2 molecules to collide with H2 molecules.

The rate slows down because collisions are less frequent.

on to Questions 54-55

 

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

Questions 51-53 Questions 54-55 Questions 56-58 Questions 59-61 Questions 62-64 Questions 65-66 Questions 67-68 Questions 69-71 Questions 72-74 Questions 75-77 Questions 78-79 Questions 80-81

 
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