110年 - [非官方正解]110 國立臺灣大學_碩士班招生考試_部分系所:物理化學(A)(基礎熱力學與反應動力學)#102143

科目：研究所、轉學考(插大)◆物理化學 | 年份：110年 | 選擇題數：14 | 申論題數：5

試卷資訊

所屬科目：研究所、轉學考(插大)◆物理化學

選擇題 (14)

1. NH4CI when dissolved in water leads to cooling sensation. The dissolution of NH4CI at constant temperature is accompanied by (A) increase in entropy, (B) decrease in entropy, (C) no change in entropy, (D) no change in enthalpy, (E) decrease in free energy.
2. Heat energy of 743 J is needed to raise the temperature of 5 moles of an ideal gas by 2 K at constant pressure. How much heat is needed to raise the temperature of the same mass of the gas by 2 K at constant volume? (A) 826 J, (B) 743 J, (C) 660 J, (D) 600 J, (E) 545 J.

3. Three samples of the same idcal gas (the ratio of heat capacitiesγ = 1.5) have equal volumes and temperatures. The volume of each sample is doubled, the process being isothermal, adiabatic, and isobaric, respectively. If the final pressures are equal for the three samples, the ratio of their initial pressure is (A) 1:1:1, (B) 2:2:1, (C) 1:2:1, (D)6167bfc1f142d.jpg (E)6167bfdf5cc4a.jpg
4. A sample of ideal gas that initially occupies 15.0 L. at 300 K and 1.0 bar is compressed isothermally. To what volume must the gas be compressed to reduce its entropy by 5.0 J/K? (A) 5.40 L, (B) 5.56 L, (C) 8.22 L, (D) 20.6 L, (E) 40.5 L.

5. The specific heats of iodine vapor and solid are 0.031 and 0.055 cal/g, respectively. If the enthalpy of sublimation of iodine is 24.0 calg at 200℃, the enthalpy of sublimation of iodine at 250℃should be (A) 24.0 cal/g, (B) 26.4 cal/g, (C) 20.8 cal/g, (D) 28.6 cal/g, (E) 22.8 cailg.

6. A solution was prepared by dissolving 7.45 g of KCI in 200 g of H20 in a calorimeter with a water equivalent of 25g. The temperature of the water had reduced from 28℃ to 25℃. △H for dissolving KCl in water is (Specific heat capacity of water is 4.2 J/K/g) (A) 2.520 hJ/mol, (B) 2.835 k/mol, (C) 20.60 kJ/mol, (D) 25.20 kJ/mol, (E) 28.35 kJ/mol.

7. The molar enthalpy of vaporization of benzene at boiling point (353 K) is 7.4 kcal/mol. The molar internal energy change of vaporization is (A) 7.400 kcal/mol, (B) 8. 106 kcal/mol, (C) 6.694 kcal/mol, (D) 62.47 kcal/mol, (E) 70.86 kcal/mol.

8. At 200℃, PCl5 dissociates as follows:6167c05eed38a.jpg It was found that the equilibrium vapors are 62 times as heavy as hydrogen. The percentage dissociation of PCl5 at 200℃ is (A) 34.1%, (B) 68.1%, (C) 40.5%, (D) 70.3%, (E) 50.6%.

9. The Deacon reaction is the oxidation of6167c0b1cac6f.jpg. At a pressure of 730 mm and with an initial mixture containing 8% HCI and 92% O2, the degree of decomposition of the HC! is 0.08. What is the equilibrium partial pressure of oxygen? (A) 566.84 mm, (B) 671.60 mm, (C) 659.92 mm, (D) 537.28 mm, (E) 670.43 mm.

10. The standard free energy of formation 6167c0f384caf.jpg are 30.426 kJ/mol for trans-1,2-dichloroethene and 22.112 kJ/mol for cis-1,2-dichloroethane at 27℃. The molar ratio of trans and cis isomers at equilibrium at 27 ℃ is (A) 2:3, (B) 3:2, (C) 28:1, (D) 1:28, (E) 10:3.

11. A quantity of 2 g of C6H5COOH dissolved in 25 g of benzene shows a depression in freezing point equal to 1.96 K. Molar depression constant for benzene is 4.9 K.kg/mol. What is the percentage association of acid if it forms double molecules (dimer) in solution? (A) 39%, (B) 78%, (C) 61%, (D) 19.5%, (E) 56%.
12. What is the order of a chemical reaction: A + 2 B → C, if the rate formation of C increases by a factor of 2.82 on doubling the concentration of A and increases by a factor of 9 on tripling the concentration B? (A) 712, (B) 7/4, (C) 5/2, (D) 5/4, (E) 2.
13. Rate of the reaction: A→products is doubled when the concentration of A is incrcased four times. If the half-life of the reaction is 16 min, at a given concentration, then the time required for 75% of the reaction to complete is (A) 24.0 min, (B) 27.3 min, (C) 48.0 min, (D) 49.4 min, (E) 52.3 min.
14. Rate of an uncatalyzed first-order reaction at 300 K is balf of the rate of catalyzed reaction at 1 50 K. Ifthe catalyst lowers the threshold energy by 20 kcal, what is the activation energy of the uncatalyzed reaction? (A) 39.58 kcal/mol, (B) 19.58 kcal/mol, (C) 40.42 kcal/mol, (D) 20.42 kcal/mol. (E) 56.68 kcal/mol.

申論題 (5)

(a) (6%) the Joule-Thomson coefficient and
(b) (6%) its constant-volume heat capacity C..

16. (6%) The equilibrium 6167c1e0c879d.jpg is first-order in both directions. Derive an expression for the concentration of A as a function of time when the initial molar concentrations of A and B are [A]0 and [B]0.

17.(6%) Consider the following mechanism for the thermal decomposition of R2:
 6167c23b16b39.jpg where R2， PA， PB are stable hydrocarbons and R and R' are radicals. Find the dependence of the rate of decomposition of R2 on the concentration of R2.

18. (6%) The cxcess Gibbs energy of a certain binary mixture (A + B) is equal to gRTx(1 - x) where g is a constant and x is the mole fraction of a solute A. Find an expression for the chenical potential of A in the mixture. The chemical potential of pure A is μA*.