所屬科目:教甄◆化學專業/化工科
1. For [H+ ] = (8.0 ± 0.4) ✕ 10-5 M, pH = 4.10 ± s. s = ? (A) 0.01 (B) 0.02 (C) 0.03 (D) 0.04
4. For two monoprotic acids (HA, HB) and their conjugate bases (A- , B- ), the following relations are known: HA + B- A- + HB, K > 1 and pKb(A- ) < 7.0. Which of the following order of K’s is correct? (A) Kb(B- ) > Ka(HB) > Ka(HA) > Kb(A- ) (B) Kb(A- ) > Kb(B- ) > Ka(HA) > Ka(HB) (C) Kb(B- ) > Kb(A- ) > Ka(HA) > Ka(HB) (D) Kb(B- ) > Ka(HA) > Kb(A- ) > Ka(HB)
5. The solubility of Ag2CrO4(s) in water is 10000 times that of Ag2CrO4(s) in 0.020 M AgNO3(aq). What is the Ksp for Ag2CrO4? (A) 2 ✕ 10-8 (B) 4 ✕10-10 (C) 1 ✕ 10-12 (D) 4 ✕ 10-12
6. Consider the concentration cell: Cu | Cu2+ (5.0 ✖ 10-5 M)||Cu2+ (0.50 M)| Cu. What is the cell potential (in volt) at 25°C? (A) 0.06 (B) 0.12 (C) 0.18 (D) 0.24 2
7. For the condensation of water vapor at 1 atm and 25°C (H2O(g) → H2O(l)), which of the following relations is correct? (A) △G < 0 (B) w < 0 (C) △S > 0 (D) q > 0
8. For an isothermal and reversible compression of an ideal gas, which of the following relations is correct? (A) △H < 0 (B) △G = 0 (C) q > 0 (D) △S < 0
13. One mole of an ideal gas (Cv = 20 J•K-1 •mol-1 ), initially at 1.0 atm and 300 K, absorbs 100 J of heat and performs 500 J of work in a certain process. What is the final temperature (in K) of the gas? (A) 280 (B) 290 (C) 300 (D) 320
18. Consider the equilibrium: PCl5(g) PCl3(g) + Cl2(g), Kc = 0.025 at 400 K. If 0.5 mol of PCl5 is placed in a 1.0 L container at 400 K and is allowed to reach equilibrium, what is the total pressure (in atm) of the gases? (A) 5 (B) 10 (C) 15 (D) 20
22. A battery is constructed from two half cells: Zn|Zn2+(1.0 M) and Mn|Mn2+(1.0 M); the volume of each electrolyte solution is 300 mL. The battery is allowed to discharge at a constant current of 9.65 amperes. Given that: F = 96500 C•mol-1 ; E° = -0.76 V for Zn2+/Zn and -1.18 V for Mn2+/Mn. Answer the following questions. (A) Indicate the anode, cathode, and direction of electron flow of the cell. 3% (B) Calculate the standard cell potential. 2% (C) The equilibrium constant of the cell reaction is K; log K = ? 2% (D) Find [Zn2+] after 10 min. of discharging. 3%
23. One mole of an ideal gas (Cv = 2R), initially at X, undergoes three reversible steps of a cycle as shown below: Answer the following questions. (ln 3 = 1.1) (A) Find the temperature (T) at state Z. 2% (B) Find the work done (w) for step (3). 2% (C) Find the change in enthalpy (△H) for step (2). 3% (D) Find the heat (q) involved in a cycle. 3%
24. After people take the medicine X, it can be absorbed into the body through pathway A→B and enter the blood. Medicine in the blood can reduce its concentration through decomposition (B→C) or excretion (B→D), as shown in the figure below:
Assume that the process A→B is much faster than those of B→C and B→D. Therefore, each time a medicine with a dose of [X]o is taken, it can be regarded as immediately producing a concentration of [X]b (= 0.020 mM) of X in the blood. Assume that B→C and B→D are both first-order processes, and their rate constants are k1 (= 0.075 h-1 ) and k2 (= 0.025 h-1 ), respectively. If a person takes the same dose ([X]o) of the medicine every t hour, answer the following questions. (A) Just after taking the medicine for the nth time, its concentration in the blood is equal to [P]n. Express [P]n as a function of [X]b, k1, k2 and t. 3% (B) Continue to take the medicine every 6 hours for a long period of time (n→∞), calculate [P]∞ (in mM)? 3% (C) Find the half-life of the medicine in the blood. 2% (D) What proportion of the decrease in medicine concentration in the blood is caused by decomposition? 2%