课程名称︰普通化学丙
课程性质︰必修
课程教师︰佘瑞琳
开课学院：理学院
开课系所︰化学系
考试日期（年月日）︰104/1/12
考试时限（分钟）：110分钟
试题 :
General Chemistry Final Exam (103-1C) 2015/01/12
Constants: R = 8.314 J/mol-K = 0.082 L-atm/mol-K; F = 96500 C/mol
I. Multiple Choice Questions: (50%; may have 1-4 correct answers/question)
1. For the biopolymer, protein
(a) The monomers are a-amino acids.
(b) It is polymerized by condensation reaction.
(c) The monomers are linked together by amide linkage.
(d) H-bonding is one of the forces that stabilize the u-helix structure of
protein.
2. For the polystyrene (PS) with the following structure
http://imgur.com/bti2n1r
(a) CHFCHC6H5 is the monomer.
(b) PS is a condensation polymer.
(c) PS is a homopolymer.
(d) PS is a polyester.
3. The following reaction was studied by the method of initial rate:
http://imgur.com/9diGSRa
(a) m = 1 (b) n = 1
(c) The reaction is second order overall.
(d) The value of rate constant k is 0.50 M-ls-
4. In a first order decomposition reaction, 50.0% of a compound decomposes in
10.5 min.
(a) The half-life of the reaction is 10.5 min.
(b) The rate constant of the reaction is 10.5 min.
(c) It takes 21.0 min. for 75.0% of the compound to decompose.
(d) We can't determine how long will it take for 75.0% of the compound to
decompose without initial concentration of the compound.
5. The addition of a catalyst in a reaction
(a) provides an alternate path with a different activation energy
(b) decrease the activation energy (E_a)
(c) increases the concentration of products at equilibrium
(d) lowers the enthalpy change in the overall reaction
6. The rate constant (k) for the gas-phase decomposition of N2O5: N2O5 →
2NO2 + 1/2 O2 has the following temperature dependence. Calculate the
activation energy of the reaction.
http://imgur.com/zi9Txul
http://imgur.com/qYLI7IK
(a) 1020 J/mol (b) 12447 J/mol
(c) 0.000831 kJ/mol (d) 103 kJ/mol
7. A proposed mechanism for the reaction of carbon dioxide with hydroxide ion
in aqueous solution is as following:
http://imgur.com/QObPzFK
(a) Step 1 is rate determining step.
(b) The molecularity of step 1 is bimolecular.
(c) The rate law deduced by the proposed mechanism is rate = k[CO2][OH-]^2.
(d) OH- is the intermediate.
→ 。
8. Consider the equilibrium: 2SO2(g) + O2(g) ← 2SO3(g) H = -99 kJ, which of
the following will shift the equilibrium to the right?
(a) Add O2 to the system at constant temperature and volume.
(b) Decrease the volume of the system to increase the pressure.
(c) Add neon (Ne) gas to the system at constant volume to increase total
pressure.
(d) Raise the temperature.
9. Which of the following ordering is correct?
(a) Acid strength: HBr02 < HBrO
(b) Acid strength: CH3COOH < CC13COOH
(c) pH: 0.10 M HCI < 0.10 M HF
(d) pH: 0.10 M NH4NO3 < 0.10 M NaCl < 0.10 M K2CO3
10.Which of the following is conjugated acid-base pair?
(a) HNO3, HNO2 (b) H+, H2 (c) H2CO3, CO3 2- (d) CH3NH3+, CH3NH2
11.In order to prepare a buffer with pH 7.8, which of the following pairs
should you choose best?
(a) HCOOH/HCOONa (Ka = 1.8 x 10^-4)
(b) CH3COOH/CH3COONa (Ka = 1.8 x 10^-5)
(c) H2CO3/NaHCO3 (Ka 4.4 x 10^-7)
(d) NaH2PO4/Na2HPO4 (Ka of H2PO4 =6.2 x 10^-8)
12.Calculate the pH of a buffer consisting of 0.50 M HF and 0.30 M NaF. For
HF(aq), Ka = 1.0 x 10^-4.
(a) 3.78 (b) 4.00 (c) 4.22 (d) none of the above
13.Consider a 25.0 mL of 0.10 M acetic acid (CH3COOH, Ka = 1.0 x 10^-5) is
titrated with 0.10 M NaOH:
(a) Before titration, the initial pH of 0.10 M CH3COOH(aq) is 1.00.
(b) After adding 12.5 mL of 0.10 M NaOH to the acid, the pH of the solution
reaches 5.00.
(c) At equivalence point, the pH of the solution is 7.00.
(d) Phenolphthalein (Ka = 1 x 10^-9) is an appropriate indicator for this
titration.
14.The solubility of silver carbonate (Ag2CO3) is 0.032 M at 20℃. Calculate
its Ksp.
(a) 3.3 x 10-5 (b) 1.3 x (c) 2.0 10-3 (d) none of the above
。
15.For the following substance, choose the one with S = 0 at 25℃?
(a) Cu(s) (b) Br2(l) (c) O2(g) (d) none of the above
16.For the followings, choose the one with positive entropy change (ΔS = O).
(a) N2(g) + 3H2(g) → 2NH3(g) (b) CaCO3(s) → CaO(s) + CO2(g)
(c) Pb2+(aq) + 2Cl-(aq) → PbCl2(s) (d) I2(s) → I2(g)
。 。
17.For the reaction 2NO(g) + Cl2(g) → 2NOCl(g), ΔH = -77.1 kJ/mol,ΔS = 121.3
J/mol-K at 25℃.
(a) It's an exothermic reaction.
(b) The entropy of the system increases.
(c) It's a spontaneous reaction at standard states and 25℃.
(d) The rate of the reaction must be very fast according to the
thermodynamic state functions.
。
18.Consider the reaction: 2SO2(g) + O2(g) → 2SO3(g) at 25℃, ΔG = -141 kJ.
Calculate the equilibrium constant K at 25℃.
(a) 0.68 (b) 1.06 (c) 5.2 x 10^24 (d) none of the above
19.For a redox reaction: 10 Cl- + 16H+ + 2MnO4 → 5Cl2 + 2Mn2+ + 8H2O
(a) Cl- is oxidized. (b) H+ is the reducing agent.
(c) MnO4- is reduced. (d) MnO4- is the oxidizing agent.
20.For an exothermic and exothermic and spontaneous redox reaction: Mg(s) +
2HCl(aq) → MgC12(aq) + H2(g) at 25℃, which of the following must be true?
(a) ΔG < 0 (b) ΔS < 0 (c) E_cell < 0 (d) ΔH < 0
21.Which of the following is state function?
(a) enthalpy, H (b) entropy, S (c) Gibbs energy, G (d) cell potential, E
22.For the fructose molecule shown as figure.
http://imgur.com/n01jcVT
(a) There are four chiral carbons in the molecule.
(b) Fructose is a ketose.
(c) Fructose is a pentose.
(d) We can distinguish a sugar that is dextrorotatory or levorotatory by
the Fischer projection.
23.Which of the following is chelating agent?
(a) en, NH2CH2CH2NH2 (b) NO2- (c) EDTA4- (d) OH-
24.The following data were collected for the decomposition of N2O5. According
to the plots obtained,what's the order of the reaction?
http://imgur.com/4B0DBzR
http://imgur.com/TXXSiGK
http://imgur.com/AzNI2I6
(a) 0 (b) 1 (c) 2
(d) none of the above
25.What's the value of rate constant?
(a) 0.0035 (b) 0.3095
(c) 0.0315 (d) none of the above
II. Problems: (60%)
l. For the glyceraldehyde with the following dashed and solid wedge line
structure.
http://imgur.com/vnwHsRg
(a) Give the absolute configuration in R, S system.
(b) Draw the mirror image of the given glyceraldehyde.
Increasing priority: -H < -CHO < -OH
2. Ammonia is a weak base that dissociate in water to a limited extent.
Calculate the Ka of NH4+.
→
NH3(aq) + H2O(l) ← NH4+(aq) + OH-(aq) Kb = 1.8 x 10^-5.
3. (a) Calculate the pH of a 0.25 M solution of sodium acetate (CH3COONa).
(b) What is the percent hydrolysis? Ka of CH3COOH = 1.8 x 10^-5.
4. Iron(II) hydroxide, Fe(OH)2, is an insoluble solid.
(a) Write the solubility product constant (Ksp) expression of Fe(OH)2.
(b) Calculate the molar solubility of Fe(OH)2 in water at 25℃, given that
Ksp = 1.0 x 10^-14.
(c) The solubility of Fe(OH)2 will increase or decrease in an acidic
solution?
5. Briefly state the three laws of thermodynamics.
6. For the reaction at 25℃: 2NaHCO3(s) → Na2CO3(s) + H2O(l) + CO2(g)
。 。 。
Calculate (a) ΔH, (b) ΔS, (c) ΔG, and (d) equilibrium constant, K, for
the reaction at 25℃.
(e) At what temperature will the reaction become spontaneous at standard
states.
http://imgur.com/soOJzEi
7. For a voltaic cell that uses Ag/Ag+ and Zn/Zn2+ half-cell reactions under
standard conditions and 298 K:
http://imgur.com/1F0WOSi
(a) Write the balanced cell reaction.
(b) Sketch the line notation for the electrochemical cell.
(c) Indicate the anode and cathode.
(d) Calculate E for the reaction.
(e) What is the value of when the reaction reaches equilibrium.
8. A concentration cell consists of two Ag/Ag+ half-cells. In half-cell A, the
electrolyte is 0.010 M AgNO3; in half-cell B, it is 4.0 x 10^4 M AgNO3.
。
(a) What is the standard cell potential, E_cell?
(b) What is the cell potential at 298 K?
9. For the complex ion [Fe(CN)6]4-, CN- is a strong field ligand.
(a) What's the oxidation number of central metal ion?
(b) What's the coordination number of central metal ion?
(c) What's the geometry of the complex ion?
(d) Draw the crystal-field energy-level diagrams, and show the placement of
electrons for the complex.
(e) Is the complex ion paramagnetic or diamagnetic?