Choose the BEST answer to the following 50 questions:

1. Consider the following statements:

I. In an endothermic reaction, the enthalpy of the products is less than enthalpy of the reactants.
II. The DG of a non-spontaneous reaction proceeding at constant T and P is positive.
III. A process that absorbs energy from its surroundings is exothermic.

a) all are correct
b) only II and III are correct
c) only I is correct
d) only II is correct
e) only III is correct

2. The DH° of the combustion for methane CH4, is - 890 kJ/mole. How many kg of methane must be burned to supply a house with 2.0 x 105 kJ daily requirement of energy?

a) 2.97 kg
b) 535 gram
c) 60.6 gram
d) -2.97 gram
e) 3.6 kg

3. The standard enthalpy of formation of glucose, C6H12O6 (s) refers to the DH° of which reaction below?

a) 6 CO2(g) + 6 H2O(l) ---> C6H12O6(s) + 6 O2(g)
b) 6 CO2(g) + 6 H2O(g) ---> C6H12O6(s)
c) C6H12O6(s) ---> 6 C(graphite) + 3 O2(g) + 6 H2(g)
d) 6 C(graphite)) + 3 O2(g) + 6 H2(g) ---> C6H12O6(s)
e) C6H12O6(s) + 6 O2(g) ---> 6 CO2(g) + 6 H2O(1)

4. Given that:

2 H2(g) + O2(g) ---> 2 H2O(l); DH° = -571 kJ/mol
C3H4(g) + 4 O2(g) ---> 3 CO2(g) + 2 H2O(l); DH° = -1941 kJ/mol
C3H8(g) + 5 O2(g) ---> 3 CO2(g) + 4 H2O(l); DH° = -2220 kJ/mol

Calculate the DH° value for the reaction C3H4(g) + 2 H2(g) ---> C3H8(g)

a) -292 kJ/mol-rxn
b) +292 kJ/mol-rxn
c) +850 kJ/mol-rxn
d) -850 kJ/mol-rxn

5. Calculate the DH° of the following reaction:

C2H4(g) + H2(g) ---> C2H6(l)

Given the standard enthalpies of formation of the following species:
 

                     Substance         DH°f
                   ---------------------------------
                      C2H4(g)       +52.3 kJ
                      C2H6(l)       -84.86kJ

a) +137.2 kJ
b) -137.2 kJ
c) +32.6 kJ
d) -32.6 kJ

6. Given that:

2 SO3(g)---> 2 SO2(g) + O2(g); DH = +197.8kJ/mol-rxn
S(s) + (3/2) O2(g) ---> SO3(g); DH = - 395.7 kJ/mol-rxn

Determine the heat of formation for SO2.

a) + 98.9 kJ/mol
b) + 197.8 kJ/mol
c) +691.8 kJ/inol
d) -296.8 kJ/mol

7. Which set of conditions FAVORS the formation of a solution between two liquids, one of which is considered the solvent?

a) Strong solvent-solvent interactions
b) Weak solvent-solute interactions
c) Strong solvent-solute interactions
d) Strong solute-solute attractions

8. In which of the following should the solubility of the solute (listed first) be LOWEST?

a) KCl in NH3(l)
b) C6H14 in CCl4
c) CCl4 in hexane, C6H14
d) S8 in water

9. Calculate the mole fraction of CH3CH2OH, ethanol (molar mass = 46.0 g/mol), in a solution that contains 100 g of ethanol and 100 g of H2O.

a) 3.56
b) 0.28
c) 0.50
d) 0.67

10. When 100.0 g of an unknown nonelectrolyte is dissolved in 500.0 g of benzene, C6H6, the solution boils at 82.9°C. Calculate the molecular weight (molar mass) of the unknown material. Kb for benzene is 2.53°C/m and the boiling point of pure benzene is 80.1°C.

a) 130 g/mol
b) 20.3 g/mol
c) 183 g/mol
d) 156 g/mol

11. The density of concentrated sulfuric acid is 1.84 g/mL. If this corresponds to 18 M, what is the molality of the solution?

a) 18 m
b) 95.5 m
c) 240 m
d) 0.240 m

12. Consider the reaction: Cl2(g) + 3 F2(g) ---> 2 ClF2(g). If the rate of appearance of ClF3, D[ClF3]/Dt, is +0.60 M/s (mole/L-s), what is the rate of disappearance of F2(g), -D[F2]/Dt?

a) 0.20 M/s
b) 0.60 M/s
c) 1.8 M/s
d) 0.90 M/s
e) 0.30 M/s

13. Suppose that the reaction in the previous problem, Cl2(g) + 3 F2(g) ---> 2 ClF3(g), is first order in F2 and second order Cl2. Which of the following is NOT TRUE?

a) If [F2] is doubled, the rate of the reaction doubles.
b) If [Cl2] is doubled, the rate of the reaction quadruples (increases by 4x).
c) If both [F2] and [Cl2] are doubled, the rate of the reaction is 8x.
d) If [F2] is doubled and [Cl2] is cut in half, the rate of the reaction remains the same.
e) The rate of the reaction is third order overall.

14. Consider a hypothetical reaction 2A + B ---> products. Given the following information concerning the initial rate of the reaction with different initial concentrations: 

                      [A]o (mole/L)         [B]o (mole/L)          Initial Rate (M/s)
     ------------------------------------------------------------------------------------
     Experiment 1        0.020               0.020                      4.20 x 10-3
     Experiment 2        0.040               0.020                      1.68 x 10-2
     Experiment 3        0.040               0.040                      6.72 x 10-2
What is the rate law which most nearly accounts for this data? Rate =Š

a) k[A]2[B]
b) k[A][B]
c) k[A][B]2
d) k[A]2[B]2
e) k[A]2

15. Ozone is often produced in the troposphere (the layer of air nearest the earth¹s surface.) Several investigations indicate that one way it can be produced is by the following sequence of reactions (mechanism.) The overall reaction is 3/2 O2 -- -> O3 (all gaseous):

NO(g) + 1/2 O2(g)---> NO2(g)
NO2(g) + light ---> NO(g) + O(g)
O2(g) + O(g) ---> O3(g)

Which of the following is TRUE?

a) There are no reaction intermediates.
b) NO(g) is the only reaction intermediate.
c) NO(g) is a catalyst.
d) Both NO(g) and O(g) are catalysts.
e) Both NO2(g) and O(g) are catalysts.

16. Nitrogen reacts with hydrogen to form ammonia:

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

An equilibrium mixture of nitrogen, hydrogen and ammonia at a given temperature is found to contain 0.30 mol/L N2, 0.40 mol/L H2 and 0.10 mol/L NH3. Calculate the value of Kc for this reaction at the given temperature.

a) 0.52
b) 1.9
c) 0.83
d) 1.2
e) 0.083

17. Consider the reaction at equilibrium in question 16. H2 is added to this reaction mixture at equilibrium. What will happen as a new equilibrium is established?

a) The Kc for the reaction will decrease.
b) The amount of N2 in the mixture will decrease.
c) The Kcof the reaction will increase.
d) The amount of NH3 will decrease.
e) The amount of N2 will increase.

18. The equilibrium constant for the reaction:

PCl3(g) + Cl2(g) <---> PCl5(g)

at a certain temperature is Kc = 1.0 x 10-12. If the initial concentrations of the two reactant species are both 1.0 M, what is the concentration of PCl5(g) when the system reaches equilibrium. (NOTE: By noting that the Kc is very small, you can use an approximation which will avoid having the apply the quadratic equation.)

a) 1.0 x 10-12M
b) 1.0 x 106 M
c) 1.0 M
d) 2.0 M

19. A reaction has an equilibrium constant, Kc = 1.0 x 10-10 and is endothermic. What of the following statements is CORRECT conclusion that one can reach from this information?

a) The product concentrations will be small compared to the reactants at equilibrium.
b) The products are thermodynamically more stable that the reactants.
c) An increase in T will cause Kc to decrease.
d) The rate of the reaction is very slow.

20. Identify the CORRECT statement regarding the reversible reaction A<--->B, which has a Kc = 20.0.

a) At equilibrium the forward reaction and the reverse reactions ceases.
b) At equilibrium the concentrations of A and B are no longer changing.
c) At equilibrium [B]/[A] = 1.0.
d) At equilibrium [B] = [A].
e) None of these statements is correct.

21. Which is NOT TRUE for the following reaction:

HCl(aq) + H2O(l) ---> H3O+(aq) + Cl-(aq)

a) Cl- is the conjugate base of HCl.
b) H3O+ is the conjugate acid of H2O.
c) This reaction is essentially 100% complete.
d) H2O is acting as a base in this reaction.
e) CF is a fairly strong base in aqueous solution.

22. Which of the following is NOT a strong base?

a) NaOH
b) KOH
c) Ca(OH)2
d) NH3

23. Of the three weak acids: HAc (acetic acid), HF, and HCN, the strongest acid is HF and the weakest acid is HCN. What can be said of the anions, Ac-, F-, and CN-?

a) All three are bases, with F- the strongest and CN- the weakest base.
b) All three are bases, with Ac- the strongest and F- the weakest base.
c) All three are bases, with CN- the strongest and F- the weakest base.
d) All three are bases, with F- the strongest and Ac- the weakest base.
e) None of these anions are bases.

24. Which of the following is the weakest acid in an aqueous system?

a) H2SO4
b) H2O
c) H2S
d) H2Te
e) H3O+

25. Which of the following bases is a Bronsted-Lowry base but is NOT a Arrhenius base?

a) NH3
b) NaOH
c) KOH
d) Mg(OH)2

26. What is the [H3O+] concentration of 0.10 M HI?

a) 0.10 M
b) 1.0 x 10-7
c) 1.0 x 10-14
d) 1.0 M
e) 0.20 M

27. Calculate the pH of a 0.20 M HF solution. (Ka for HF = 7.2 x 10- 4)

a) 3.1
b) 1.6
c) 4.1
d) 1.9

28. Calculate the pH of a solution which is 0.10 M in HF(aq) and 0.20 M in NaF(aq). (Ka for HF = 7.2 x 10-4)

a) 3.44
b) 3.14
c) 2.84
d) 1.00
e) -3.14

29. Given the Ka of HF is 7.2 x 10-4, what is the Kb of the F- ion in aqueous solution?

a) 1.0 x 10-14
b) 1.4 x 103
c) 1.4 x 10-11
d) 7.2 x 10-4

30. Which salt produces a basic solution when dissolved in water?

a) NaCl
b) BaCl2
c) NaF
d) NH4Cl
e) KBr

31. Which of the following is NOT a characteristic of a titration of a strong acid with a strong base? Assume the base is being added incrementally to the acid. (Choose the FALSE statement.)

a) The pH at the equivalence point is greater than 7.00.
b) At the equivalence point the number of equivalents of acid equals the number of equivalents of base.
c) An indicator is used to determine the endpoint.
d) The pH increases as the titration progresses.
e) The pH rises sharply near the equivalence point.

32. A 100.0 mL sample of a 0.100 M solution of a weak monoprotic acid is titrated with 0.100 M NaOH(aq). How many mL of NaOH(aq) have been added when the [H+] = Ka for the acid?

a) 0.00 mL
b) 25.00 mL
c) 50.00 mL
d) 75.00 mL
e) 100.0 mL

33. One liter of water is saturated with HgI2(s), and the concentration of Hg2+= 2.2 x 10-10 M. What is the Ksp of HgI2? The reaction is HgI2(s) <---> Hg2+(aq) + 2I- (aq).

a) 4.8 x 10-20
b) 4.3 x 10-29
c) 9.7 x 10-20
d) 7.3 x 10-18
e) 6.0 x 10-23

34. BaSO4 is precipitated by mixing BaCl2(aq) with Na2SO4(aq). Which of the following MUST be TRUE at equilibrium? (Choose the TRUE statement under all conditions.) Ksp for BaSO4 =1.1 x 10-10.

a) [Ba2+] = [SO42-]
b) [Ba2+] + [SO42-] = 1.1 x 10-10
c) [Ba2+] = 2[SO42-]
d) [Ba2+][SO42-] = 1.1 x 10-10
e) [Ba2+] = [SO42--] = 0.00

35. The Ksp for AuCl3 = 2.0 x 10-23. What is the molar solubility (in moles/L) of AuCl3 in a saturated solution of AuCl3? Assume AuCl3 dissolves as: AuCl3 <---> Au3++ 3 Cl- .

a) 2.7 x 10-10
b) 1.0 x 10-23
c) 2.1 x l0-6
d) 4.5 x 10-12
e) 9.3 x 10-7

Use the following table of Ksp values for questions 36 and 37: 

          Solid               Ksp 
        --------------------------------
          CdS              3.6 x 10-29
          AgCl             2.0 x 10-13
          Ni(OH)2          2.8 x 10-16
          AgI              1.5 x 10-16
          PbS              8.4 x 10-28


36. Which of these salts has the smallest molar solubility?

a) CdS
b) AgCl
c) Ni(OH)2
d) AgI
e) PbS

37. Which of these salts has the greatest molar solubility?

a) CdS
b) AgCl
c) Ni(OH)2
d) AgI
e) PbS

38. A beaker containing 20.00 mL of 0.0200 M FeCl2(aq) solution is mixed with 20.0 mLof a solution which is 0.0200 M Pb(NO3)2(aq). What will happen? Ksp for PbCl2 is 1.7 x 10-5. Ksp for Fe(NO3)2 is "large."

a) Fe(NO3)2(s) will precipitate.
b) PbCl2 will precipitate.
c) Both PbCl2 and Fe(NO3)2 will precipitate.
d) Nothing will precipitate.

39. A solution contains Ba2+, Pb2+, and Sr2+, all at 0.0100 M. Na2SO4(s) is added in very tiny increments without substantially changing the volume of the solution. What will be the identity of the first precipitate that forms? (that is, the solid formed with the lowest SO42- concentration)

Ksp for BaSO4 = 1.1 x 10-10
Ksp for PbSO4 = 1.8 x 10-8
Ksp for SrSO4 = 2.7 x 10-7

a) BaSO4
b) PbSO4
c) SrSO4
d) all three will precipitate at the same point

40. A solution has a Mg2+concentration of 0.025 M. What is the maximum possible concentration of F- that can exist before MgF2 begins to precipitate? Ksp for MgF2 is 6.4 x 10-9.

a) 5.1 x 10-4
b) 6.4 x 10-9
c) 2.6 x 10-7
d) 2.3 x 10-10
e) 1.0 x 10-15

41. Consider the reaction MnO2 + Br- ---> Mn2+ + Br2 in aqueous acid. When this reaction is balanced with the smallest set of whole numbers, which of the following is true? (Choose the TRUE statement.)

a) The coefficients for MnO2 and Br- are both 1.
b) Four H+ ions are consumed as reactants.
c) The coefficient of Br2 is 2.
d) Water is consumed as a reactant.

42. Consider the redox reaction: TeO2 + 4 H+(aq) + 2 Hg(l) ---> Te(s) + 2 H2O(l) + Hg2+(aq). What is the reducing agent in this reaction?

a) TeO2
b) H+
c) Hg
d) there is no reducing agent in this reaction

43. Consider the balanced reaction: 2 Cl2 + 4 OH- ---> 4 Cl- + O2(g) + H2O. How many moles of electrons are being transferred per mole of O2 formed?

a)1
b)2
c)3
d)4
e)8

44. Consider a spontaneously operating electrochemical cell in which the net oxidation- reduction reaction is: 3 Zr(s) + 4 Fe3+ ---> 3 Zr4++ 4 Fe(s). Choose the statement which is FALSE.

a) The anode reaction is Zr ---> Zr4++ 4e-.
b) The cathode reaction is Fe3+ + 3e- ---> Fe.
c) Electrons flow from the cathode to the anode.
d) The standard potential for this cell will be > 0.
e) Fe3+ is acting as the oxidizing agent.

45. The standard reduction potentials for the reduction of thallium, Tl, and zinc, are:

Tl+ + e- ---> Tl; E° = -0.34v
Zn2+ + 2e- --->Zn ; E° = -0.76v

What is the E° for an electrochemical cell whose reaction is Zn(s) + 2 Tl+---> Zn2+ + 2 Tl(s)?

a) -1.10 v
b) +0.08 v
c) +1.10 v
d) +0.42 v
e) -0.08 v

46. Suppose an electrolytic cell is operating at 0.50 amps. The cathode reaction in this cell is the reduction of Rh2+to Rh(s), Rh2+ + 2e- ---> Rh(s). How long must the cell operate to deposit 1.000 g of Rh?

a) 3750 s
b) 428 s
c) 1880 s
d) 7500 s
e) 4700 s

47. Which of the following statements is FALSE?

a) Nuclides with atomic number greater than 83 are unstable.
b) Nuclides with an odd number of protons and an odd number of neutrons are usually stable.
c) The ratio of neutrons to protons in a nuclide is an important factor for the stability.
d) An unstable nuclide will undergo some form of radioactive decay.

48. 14460Nd is an alpha emitter. What is the product of this radioactive decay?

a) 14458Ce
b) 14462Sm
c) 14058Ce
d) 14258Ce
e) none of these

49.21382Pb is known to be radioactive. If the product of the decay is 21383Bi, which type of radioactive decay it occurring?

a) positive beta (positron)
b) electron capture
c) either positron emission or electron capture
d) alpha
e) negative beta

50. Suppose 25499Es undergoes spontaneous fission to form 9841Nb, 3 neutrons, and one other nuclide.

25499Es ----> 9841Nb + 15558X + 3 10n
What must the nuclide X be?

a) 15458Ce
b) 15358Ce
c) 15657La
d) 15656Ba
e) none of these

KEY

1)d 2)e 3)d 4)a 5)b 6)d 7)c 8)d 9)b 10)c 11)c 12)d 13)d 14)d 15)c 16)a 17)b 18)a 19)a 20)b 21)e 22)d 23)c 24)b 25)a 26)a 27)d 28)a 29)c 30)c 31)a 32)c 33)b 34)d 35)e 36)a 37)c 38)d 39)a 40)a 41)b 42)c 43)d 44)c 45)d 46)a 47)b 48)c 49)e 50)b