Ch. 15, 16, & 19.7  equilibirum I                    test                   90 points                      AP chemistry

Show your work in an organized manner, include (i) any relevant equation (or formula), (ii) conversion factor(s), (iii) put the proper units in your calculations and answer, and (iv) 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. What’s the pH of 125 mL of 75 mM lactic acid ?  [10 points]

2. In regards to the reaction:  N2(g)  +  H2(g)   →  NH3(g), what’s the effect on the amount of NH3 after the disturbance to the system by  __;  justify / rationalize your response.  [15 points]

a.  decrease in volume at constant temperature

b.  addition of an inert gas, He, under constant volume and temperature conditions

c. Cooling

3.  In regards to the reaction:  H2(g)  +  Cl2(g)  →  2 HCl(g),  the initial concentration of H2, Cl2, and HCl are 1.0 M, 2.0 M and 9.0 M, respectively.  What is the equilibrium [HCl] ?  The value of the Kp = 3.0  at 300 K.  [10 points]

4.   A reaction, where Δ G > 0, is not spontaneous, yet in the 2nd step in glycolysis

Glucose-6-phospate  →  fructose-6-phosphate                                                            Δ Gº  >  0

the reaction does occur in cells; rationalize / basis for this reaction to occur.  [10 points]

5. What’s the pH of 75 mL of 125 mM sodium formate ?  [15 points]

6.  What’s the pH of 35 mL of 25 mM of ___ ?  [10 points]

a. Nitric acid

b.  Lithium hydroxide

7.   old topics:  [20 points]

a. What is the relative lattice energy of calcium oxide versus barium oxide ?  Justify / rationalize your answer.

b.  What is the bond angle and the name of the shape of SeH2  ?

c. In regards to the reaction:  N2(g)  +  H2(g)   →  NH3(g), if  dNH3_dt  =  18 mM / minute, then  dH2_dt  ?

d. In the reaction:  at STP, 5.0 L N2(g)  +  12.0 L H2(g)   →   __ g NH3(g)  ?