Name:  ______________________________           period 6                             date:  _______

Ch.  15 & 16  equilbrium  test            [90 points]                   AP  Chemistry

For problems involving calculations, show the relevant equation (or formula and conversion factor(s)), show your work in an organized manner, put the proper units in your calculations / answer, and have the proper number of significant figures in your answer. 

Academic Honesty:   The answers on this test are my own and I am using only the allowed set of notes as described in the syllabus.  I have not discussed the test questions with anyone before or during the test nor have I seen the test questions prior to the exam.  If you violate any of the preceding items or do not sign, your semester grade is a F.

                                                                        Signature:  ___________________

1.   Properties of the equilibrium constant.    If  N2 (g)   +  3 H2 (g)     <->  2 NH3 (g)          Kc = 10   at 25 °C, then  [15 points]

a.  Kp =   ___

b.  Kc =  __   for   ½ N2 (g)   +  3/2  H2 (g)     <->   NH3 (g)         

c.  Kp =  __  for    4 NH3 (g)    <->   2 N2 (g)   +  6 H2 (g)    


2.  In the reaction, N2   +  H2   ->  NH3 , the initial concentration of N2 , H2 , and NH3 are 1.0, 2.0, and 5.0 mM, respectively.  At equilibrium, the concentration of H2 is 1.2 mM.  What is the value of Kc at 45 °C ?  [10 points]

3.  What is the value of Kc at 35 °C for the synthesis of ammonia from hydrogen and nitrogen ; all chemicals are gases ?  [10 points]


4.  In the reaction   HCl(g)   +  NH3 (g)   <->  NH4 Cl (s)    at equilibrium, was disturbed by  ___;  what is the effect on the amount of NH4 Cl and HCl ?  Justify your answer.   [15 points]

a.  addition of helium

b.  cooling the system

c.  removal of ammonia


5.  What is the pH of a 2.0 L solution of  ___.   [30 points]

a.  10.0 mM formic acid

b.  10.0 mM hydrazine

c.  10.0 mM sodium propionate


6.  old topic.  Describe & rationalize the periodic trends in the first ionization energy of atoms in a __ in the Periodic table.  [10 points]

a.  row

b.  column