GPC - Dunwoody (Dr. Kim)                                      Calculator & Model # ____________

Use a Scantron for Multiple Choices (4pts), back of this page for a Big Question (8pts).

R=8.3145J/(K^.mol); 1cal=4.184J; 1mi=1.609km; 1yd=0.9144m; 1gal=3.785L; 1lb=16oz=453.6g;
1atm=101,325Pa; d(water)=0.997g/mL; d(Hg)=13.6g/mL; N_A=6.022x10²³/mol; c=2.9979x10⁸m/s;

Note:  This Sample Test #3 covers

(1) the later part of Chemical Kinetics, (2) The Chemical Equilibria (Gaseous), (3) the introductory Acid/Base Equilibria.

Given a two-step mechanism for I^--catalyzed decomposition of hydrogen peroxide (an antiseptic)

H₂O₂ + I^- -> H₂O + IO^- (slow)
H₂O₂ + IO^- ->H₂O + O₂ + I^-(fast)

1. Which is the intermediate ?
A(H₂O₂), B(I^-), C(H₂O), D(O₂), E(IO^-).

2. The rate is equal to  a(k[H₂O₂][I^-]),  b(k[H₂O₂][IO^-]),
because it is the (c) slow, (d) fast step that determines the rate.
A(a,c), B(a,d), C(b,c), D(b,d), E(-).

3. The reaction is A(0th), B(1st), C(2nd), D(3rd), E(4th) -order overall.

4. The catalyst(I^-) (a) speeds up, (b) slows down, (c) does not influence the reaction rate,
by (d) raising, (e) lowering an activation energy of the reaction.
A(a,d) B(a,e) C(b,d) D(b,e) .

                                            *       *       *       *       *       *       *

5. The automobile catalytic converter contains A(Cu), B(Fe), C(Zn), D(Pt) catalyst.

CO_(g)+3H_2(g) == CH_4(g)+H₂O_(g),    DH^o=-206.2kJ; K_c=3.92 at 1200 K.

6.  3.00 mol of CO and 3.00 mol of H₂ are placed in a 1.00 L vessel at a certain temperature and
allowed to come to an equilibrium. If the equilibrium  mixture is found to contain 0.50 mol of H₂O,
what is the amount of H₂ left in the mixture?
A(0.50), B(1.00), C(1.50), D(2.00), E(2.50) mol.

7. H₂O being removed from the system,
then the equilibrium shifts to the A(right), B(left), C(neither).

8. When the applied pressure is increased, the equilibrium shifts to the a(right), b(left),
because the forward reaction c(in-), d(de-), creases the volume.
A(a,c), B(a,d), C(b,c), D(b,d), E(-).

9. When the temperature is increased, the equilibrium shifts to the (a) right, (b) left,
because the forward reaction (c) generates, (d) consumes heat.
A(a,c), B(a,d), C(b,c), D(b,d), E(-).
 

10. When a catalyst(Ni) is added, the equilibrium shifts to the A(right), B(left), C(neither).

11. The equilibrium constant expression for the reaction is
A([CO][H₂]/([CH₄][H₂O])),   B([CO][H₂]³/([CH₄][H₂O])),
C([CH₄][H₂O]/([CO][H₂])),   D([CH₄][H₂O]/([CO][H₂]³)), E([CH₄][H₂O]/([CO]³[H₂]))..

12. A reaction quotient for a mixture with 1.0 M in each species (CO, H₂, CH₄, & H₂O) is
a(0.1),  b(1),   c(10);   so a d(forward), e(reverse) reaction will occur.
A(a,d), B(a,e), C(b,d), D(b,e), E(c,d).

13. The reaction mixture above is allowed to reache an equilibrium at 1,200 K.
What is the equilibrium concentartion of  methane, CH₄ ?  (           ) M.

14. K_c of the reaction at 600 K is ca. A(4x10^-9), B(4x10^-6), C(4x10^-3), D(0.4), E(4x10⁹).

16.  Give the equilibrium constant expression, K_c, for the following reaction
        Fe³⁺(aq) + 3OH^- (aq) ==  Fe(OH)₃(s)
       K_c = (                   )

18.  Given the oxidation of N₂ :  N₂ (g) + O₂ (g) ==  2NO(g) ;    DH^o= 180.5kJ;  Kc= 4.6x10^-31 at 25^oC.
Estimate the equilibrium concentration of NO in the air using the molar concentration of N₂  and O₂   from above question. A(6x10^-9 ), B(6x10^-15 ),C(6x10^-18 ), D(1x10^-21 ) M.

19.  Find the equilibrium constant for the reaction above at an auto engine temperature(2,000^oC).
       K_c = (                       )

20. Then calculate an equilibrium concentration of NO inside an engine to answer the following.
                (                       )

21. Concentration of NO in an engine is about A(1x10³ ), B(1x10⁷ ),C(1x10¹¹ ) D(1x10¹⁴ ) times
higher than that of NO in a normal atmosphere, thus polluting air when they exit the engine
 

22. The conjugate acid of H₂O is  (A)H₃O⁺, (B)NH₃ , (C)OH, (D) NH₄⁺.

23. If H₃O⁺ is stronger acid than NH₄⁺, then the reaction is favored for (A)  forward  , (B) reverse  direction:

24. H₃O⁺ is (a) stronger, (b) weaker acid than NH₄⁺,  because H-O bond is (c) more, (d) less polar
      than H-N bond in NH₄⁺.     A(a,c), B(a,d), C(b,c), D(b,d).

25.  Broensted-Lowry acid is  a(n)
        A(H⁺ Doner), B(H⁺ Acceptor), C(Electron-pair doner), D(Electron-pair Acceptor).

26.  What influences strength of a binary acid, HX ?
       (A) Electronegativity of X,  (B) Size(radius) of X,  (C) Both A & B, (D) Neither A nor B.

27. a(HI),  b(H₂Te) is the stronger acid, because  I  is (c) more, (d) less,
      electronegative than Te.   A(a,c), B(a,d), C(b,c), D(b,d).

28. (A) SO₃, (B)Cl₂O₇, (C)CaO, (D) Na₂O is the least ionic oxide among four:
       it will yield the most acidic solution when dissolved in water.

29. Which one is the strongest acid?  (A)HCl, (B)HClO, (C)HClO₂, (D)HClO₃, (E)HClO₄.

30. Which set contains all Lewis acids?
(A) HCl, HNO₃, H₂SO₄, H₃PO₄,HC₂H₃O₂.
(B) HClO, H⁺, SO₃, BF₃, Ag⁺..
(C) H⁺, NH₄⁺, SO₃, BF₃, Ag⁺.
(D) NH₄⁺,  CO₂, BF₃, Al³⁺ .
(E) H⁺, CO₂, BF₃, Al³⁺.

31. Which one is the strongest base?
A(Be(OH)₂), B(Mg(OH)₂), C(Ca(OH)₂), D(Sr(OH)₂),E(Ba(OH)₂).

32. Which one is amphiprotic ?
(A)H₂CO₃, (B)HCO₃^-, (C) CO₃^{2 -}, (D) HSO₄^-, (E)  B & D.

33.  Pure water in its liquid state undergo a (a) full, (b) partial, ionization
because the H-O in  H₂O molecule is c(ionic), d(polar), e(full covalent).
A(a,c), B(a,d), C(b,c), D(b,d), E(b,e).

34. A fraction of H₂O molecules ionized (=degree of ionization of water) in pure water is about
two A(thousandths), B(millionths), C(billionths), D(trillionths, 10^-12), E(quadrillionths, 10^-15).

35. [H⁺] and pH of 0.05 M HCl solution.    (            ),    (             ).

36. Which species is the second most abundabt in 0.05M HCl solution ?  (               )

37. Find pH of 0.005M NaOH solution.     (         ).

38. Which species is the second most abundant in 0.005M NaOH solution ?  (               )

39. pH of normal arterial blood is 7.4. Molarity of H⁺ must be
A(4x10⁷), B(4x10^-6), C(4.0x10^-7), D(4x10^-8).

40. Normal rain water has a pH of 5.7: so, concentration(in mM) of H₂CO₃ (K_a1=4.3x10^-7; K_a2=4.8x10^-11)
in the rain is about (A)100, (B)10, (C)1.0, (D)0.1, (E)0.01 mM.

41. As temperature increases, ion product of H₂O(K_w=1.0x10^-14 at 25^oC) (a) in-, (b) de-, creases,
because the ionization is c(endo-), d(exo-) thermic.
A(a,c), B(a,d), C(b,c), D(b,d), E(-).

42. A degree of ionization of a weak acid is (a) directly, (b) inversely, proportional to the square root of its concentration; the degree is directly proportional to (c)the square root, (d) first power, (e) second power of its K_a.
A(a,c), B(a,d), C(a,e), D(b,c), E(b,d), F(b,e).

43. Predict pH of the 0.0000075 M solution of morphine(C₁₇H₁₉NO₃, an alkaloid) (K_b=1.6x10^-6).
(A) 5.5, (B) 5.6, (C) 8.4, (D) 8.5, (E) 8.9.

44. Morphine(Mor) ionizes by picking up H⁺ from water (as does NH₃) to form HMor⁺ ion:
Mor_(aq)+H₂O_(l) == Hmor⁺_(aq)+OH^-_(aq)
The stronger acid and the stronger base are,
A(H₂O, OH^-); B(HMor⁺, OH^-); C(H₂O, Mor); D(HMor⁺,;Mor); E(-), respectively,

45. Rate constants(k) for the reaction, H_2(g)+I_2(g) == 2HI_(g), is 2.7x10^-4L/(mol^.s) at 600K and 3.5x10^-3L/(mol^.s) at 650K.
(1) Find the activation energy(E_a).
(2) Predict a rate constant value at 670K.

I. Explain with a diagram how a hydrogenation of C₂H₄ to C₂H₆ is facilitated on a Pt surface.

II. The equilibrium constant(K_c) for the reaction is 49.7 at 458^oC: H_2(g) +I_2(g) == 2HI_(g)

Find equilibrium concentrations of all species when it started with 5.00 M H₂ and 1.00 M I₂.

III. What are the concentrations of (1) H⁺ and pH, (2) acetate ion, (3) neutral acetic acid, and (4) the degree of ionization, in a solution of 0.010 M acetic acid, HC₂H₃O₂? (K_a=1.7x10^-5)

IV. You start with a mixture of 1.00 mol CO and 4.00 mol H₂ in a 10.0 L vessel for the catalytic methanation above. (1) Set up an equation with x being an equilibrium concentration of methane. (2) Solve it to find the equilibrium concentrations of all species.

V.  pH of 1.00x10^-8M HCl solution to three digits is A(8.00), B(7.04), C(7.00), D(6.98), E(6.96).