REVIEW Q’S

A titration of an acid and base to the equivalence point results in a noticeably acidic solution. It is likely this titration involves A. a strong acid and a weak base.B. a weak acid and a strong base.C. a weak acid and a weak base (where Ka equals Kb).D. a strong acid and a strong base.

For PbCl2 (Ksp = 2.4 10–4), will a precipitate of PbCl2 form when 0.10 L of 3.0 102 M Pb(NO3)2 is added to 400 mL of 9.0 102 M NaCl?

A. Yes, because Q > Ksp.

B. No, because Q < Ksp.

C. No, because Q = Ksp.

D. Yes, because Q < Ksp.

The molar solubility of magnesium carbonate is 1.8 104 mol/L. What is Ksp for this compound?

A. 1.8 104 B. 3.6 104

C. 1.3 107 D. 3.2 108 E. 2.8 1014

The solubility product for chromium(III) fluoride is Ksp = 6.6 1011. What is the molar solubility of chromium(III) fluoride?A. 1.6 103 MB. 1.2 103 MC. 6.6 1011 MD. 2.2 103 ME. 1.6 106 M

Calculate the concentration of chloride ions in a saturated lead(II) chloride (Ksp = 2.4 104) solution.

A. 2.4 104 M B. 4.8 104 MC. 3.9 102 MD. 1.2 101 M E. 7.8 102 M

Calculate the minimum concentration of Cr3+ that must be added to 0.095 M NaF in order to initiate a precipitate of chromium(III) fluoride. (For CrF3 , Ksp = 6.6 1011.)A. 0.023 M B. 0.032 MC. 7.7 108 MD. 2.9 109 M E. 6.9 1010 M

Will a precipitate (ppt) form when 300. mL of 5.0 105 M AgNO3 are added to 200. mL of 2.5 107 M NaBr? Answer yes or no, and identify the precipitate if there is one.

A. Yes, the ppt is AgNO3(s).B. Yes, the ppt is AgBr(s).C. Yes, the ppt is NaBr(s).D. Yes, the ppt is NaNO3(s).E. No, a precipitate will not form.

Arrange the following substances in the order of increasing entropy at 25C.

HF(g), NaF(s), SiF4(g), SiH4(g), Al(s)

lowest highestA. SiF4(g) < SiH4(g) < NaF(s) < HF(g) < Al(s) B. HF(g) < Al(s) < NaF(s) < SiF4(g) < SiH4(g)C. Al(s) < NaF(s) < HF(g) < SiH4(g) < SiF4(g)D. Al(s) < HF(g) < NaF(s) < SiF4(g) < SiH4(g)E. NaF(s) < Al(s) < HF(g) < SiF4(g) < SiH4(g)

Which response includes all the following processes that are accompanied by an increase in entropy? 1. 2SO2(g) + O2(g) SO3(g)2. H2O(l) H2O(s)3. Br2(l) Br2(g)4. H2O2(l) H2O(l) + (1/2)O2(g)

A. 1, 2, 3, 4 B. 1, 2 C. 2, 3, 4 D. 3, 4 E. 1, 4

Which response includes all the following processes that are accompanied by an increase in entropy?

1. I2(s) I2(g)2. 2I(g) I2(g)3. 2NH3(g) N2(g) + 3H2(g)4. Mg2+(aq) + 2OH(aq) Mg(OH)2(s)

A. 1, 2 B. 1, 3 C. 3, 4 D. 3 E. 2, 4

Determine S for the reaction SO3(g) + H2O(l) H2SO4(l).

S(J/K·mol) SO3 256.2 H2O 69.9 H2SO4 156.9

A. 169.2 J/K·mol B. 1343.2 J/K·mol C. 169.2 J/K·molD. 29.4 J/K·mol E. 29.4 J/K·mol

A negative sign for G indicates that, at constant T and P,

A. the reaction is exothermic. B. the reaction is endothermic. C. the reaction is fast. D. the reaction is spontaneous. E. S must be > 0.

Calculate G for the reaction 3NO2(g) + H2O(l) 2HNO3(l) + NO(g).

Gf (kJ/mol) H2O(l) 237.2 HNO3(l) 79.9 NO(g) 86.7 NO2(g) 51.8

A. 8.7 kJ/mol B. 192 kJ/mol C. 414 kJ/mol D. 192 kJ/mol E. 155 kJ/mol 

Ozone (O3) in the atmosphere can reaction with nitric oxide (NO): O3(g) + NO(g) NO2(g) + O2(g).

Calculate the G for this reaction at 25C. (H = 199 kJ/mol, S = 4.1 J/K·mol)

A. 1020 kJ/mol B. 1.22 103 kJ/mol C. 2.00 103 kJ/molD. 1.42 103 kJ/mol E. 198 kJ/mol 

For the reaction H2(g) + S(s) H2S(g), H = 20.2 kJ/mol and S = +43.1 J/K·mol. Which of the following statements is true?

A. The reaction is only spontaneous at low temperatures.B. The reaction is spontaneous at all temperatures.C. G becomes less favorable as temperature increases.D. The reaction is spontaneous only at high temperatures.E. The reaction is at equilibrium at 25C under standard conditions.

At 1500C the equilibrium constant for the reaction CO(g) + 2H2(g) CH3OH(g) has the value Kp = 1.4 107. Calculate G for this reaction at 1500C.

A. 105 kJ/mol B. 1.07 kJ/mol C. 233 kJ/molD. 105 kJ/molE. 233 kJ/mol

The element oxygen was prepared by Joseph Priestley in 1774 by heating mercury(II) oxide: HgO(s) Hg(l) + (1/2)O2(g), H = 90.84 kJ/mol. Estimate the temperature at which this reaction will become spontaneous under standard state conditions. S(Hg) = 76.02 J/K·molS(O2) = 205.0 J/K·molS(HgO) = 70.29 J/K·mol

A. 108 K B. 430 K C. 620 K D. 775 K E. 840 K

Calculate the equilibrium constant for the decomposition of water, 2H2O(l) 2H2(g) + O2(g) at 25C, given that Gf (H2O(l)) = –237.2 kJ/mol. A. 0.83 B. 6.3 1084 C. 2.5 1042 D. 1.6 1083 E. 4.7 105

Complete and balance the following redox equation. When properly balanced using the smallest whole-number coefficients, the coefficient of S is 

H2S + HNO3 S + NO (acidic solution) 

A. 1 B. 2 C. 3 D. 5 E. 6  

Complete and balance the following redox equation. What is the coefficient of H2O when the equation is balanced with the set of smallest whole-number coefficients? 

H2O + MnO4 + I MnO2 + IO3

(basic solution) 

A. 1 B. 2 C. 4 D. 10 E. None of these.

Given the following notation for an electrochemical cell   Pt(s) | H2(g) | H+(aq) || Ag+(aq) | Ag(s),

what is the balanced overall (net) cell reaction? 

A. 2H+(aq) + 2Ag+(aq) H2(g) + 2Ag(s) B. H2(g) + 2Ag(s) H+(aq) + 2Ag+(aq)C. 2H+(aq) + 2Ag(s) H2(g) + 2Ag+(aq)D. H2(g) + Ag+(aq) H+(aq) + Ag(s)E. H2(g) + 2Ag+(aq) 2H+(aq) + 2Ag(s)

Consider an electrochemical cell constructed from the following half cells, linked by a KCl salt bridge.

• a Fe electrode in 1.0 M FeCl2 solution • a Sn electrode in 1.0 M Sn(NO3 )2 solutionWhen the cell is running spontaneously, which choice includes only true

statements and no false ones?A. The tin electrode loses mass and the tin electrode is the cathode. B. The tin electrode gains mass and the tin electrode is the cathode. C. The iron electrode gains mass and the iron electrode is the anode. D. The iron electrode loses mass and the iron electrode is the cathode. E. The iron electrode gains mass and the iron electrode is the cathode.

 

A certain electrochemical cell has for its cell reaction:  

Zn + HgO ZnO + Hg 

Which is the half-reaction occurring at the anode?  

A. HgO + 2e Hg + O2

B. Zn2+ + 2e Zn C. Zn Zn2+ + 2e D. ZnO + 2e Zn

Calculate the value of Ecell for the following reaction: 2Au(s) + 3Ca2+(aq) 2Au3+(aq) + 3Ca(s)  A. 4.37 V B. 1.37 V C. 11.6 V D. 1.37 V E. 4.37 V

Calculate Ecell for a silver-aluminum cell in which the cell reaction is

Al(s) + 3Ag+(aq) Al3+(aq) + 3Ag(s) 

A. 2.46 V B. 0.86 V C. 0.86 V D. 2.46 V E. none of these

Consider an electrochemical cell based on the following cell diagram: 

Pt | Pu3+(aq), Pu4+(aq) || Cl2(g), Cl (aq) | Pt 

Given that the standard cell emf is 0.35 V and that the standard reduction potential of chlorine is 1.36 V, what is the standard reduction potential E(Pu4+/Pu3+)? 

A. 2.37 V B. 1.01 V C. 1.71 V D. 1.01 V E. 1.71 V

An electrochemical cell based on the following reaction has a standard cell voltage (Ecell) of 0.48 V:  

Sn(s) + Cu2+(aq) Sn2+(aq) + Cu(s) 

What is the standard reduction potential of tin(II)? (E(Cu2+/Cu) = 0.34 V) 

A. 0.14 V B. 0.14 V C. 0.82 V D. 0.82 V E. none of these

According to the following cell diagram, which chemical species undergoes reduction?  

Sn | Sn2+ || NO3 (acid soln), NO(g) | Pt

 A. Sn B. Sn2+ C. NO3

D. NO E. Pt 

In the following half equation, which is the oxidizing agent?

NO3(aq) + 4H+(aq) + 3e NO(g) + 2H2O

 A. NO3

B. H+ C. e D. NO E. H2O  

Which statement is true for a spontaneous redox reaction carried out at standard-state conditions?  

A. Ered is always negative. B. Ecell is always positive. C. Eox is always positive. D. Ered is always positive.

Which one of the following reactions will occur spontaneously at standard-state conditions and 25C? 

A. Mg2+ + Ca Mg + Ca2+

B. Au + 3K+ Au3+ + 3KC. 2Al3+ + 3Fe 2Al + 3Fe2+

D. Cu + 2H+ Cu2+ + H2

Consider the following standard reduction potentials in acid solution:E(V)

Al3+ + 3e Al(s) 1.66AgBr(s) + e Ag(s) + Br +0.07Sn4+ + 2e Sn2+ +0.14Fe3+ + e Fe2+ +0.77

 The strongest oxidizing agent among those shown above is

 A. Fe3+. B. Fe2+. C. Br. D. Al3+. E. Al.

 

Using a table of standard electrode potentials, decide which of the following statements is completely true. 

A. Cu2+ can oxidize H2, and Fe can reduce Mn2+.B. Ni2+ can oxidize Cu2+, and Fe2+ can reduce H+.C. Fe2+ can oxidize H2, and Fe2+ can reduce Au3+.D. Br2 can oxidize Ni, and H2 can reduce Mn2+.E. H+ can oxidize Fe, and Ni can reduce Br2.

Determine the equilibrium constant, Keq, at 25C for the reaction 2Br (aq) + I2(s) Br2(l) + 2I (aq)

 A. 5.7 1019

B. 18.30C. 1.7 1054

D. 1.9 1018

E. 5.7 1055

 

Consider the reaction Fe + Sn2+(1.0 M) Fe2+(1.0 M) + Sn. a. Calculate the voltage theoretically generated by the cell.b. Sketch a diagram of such a cell. Be sure to label the anode and cathode, and show the direction of electron flow in the external circuit. Write the half-reactions occurring at the electrodes.c. Show the direction in which the Cl ions in the KCl salt bridge will flow.