課程名稱︰普通化學 課程性質︰必修 課程教師︰林萬寅 開課學院：理學院 開課系所︰化工系 考試日期（年月日）︰2012/4/18 考試時限（分鐘）：110min 是否需發放獎勵金：要 謝謝 （如未明確表示，則不予發放） 試題 : 1. Pt(Z=78) forms a diamagnetic compound [Pt(en)2(CN)2]2+[PtCl2(CN)2]2-, where en= ethylenediamine (NH2CH2CH2NH2) and C is the coordinating atom for the cyanato group (CN-). Answer the following questions. (A) Give the oxidation states and the number of d electrons for Pt in both ions. [4%] (B) Name this coordination compound. [3%] (C) Give the d-electron configurations for the complex cation and aion.[4%] (D) Draw all possible structures for [Pt(en)2(CN)2]2+. [6%] (E) Draw all possible structures for [PtCl2(CN)2]2-. [4%] (F) Estimate the crystal field stabilization energy for [Pt(en)2(CN)2]2+[4%] 2. If each O2 molecule undergoes 4.40*10^9 collisions per second in a 30.0-L container at 300K and 1.00 atm, answer the following questions. (A) Calculate the average speed of O2 molecule. [4%] (B) Find the mean free path of O2 molecule. [4%] (C) Estimate the molecular diameter (in nm) of O2. [4%] (D) Estimate the van der Waal's constant b (in L*mol^-1) of O2 ,which is roughly four times its molar molecular volume. [4%] (E) If the container is compressed to 1.00L and simultaneously cooled to 200K, the compressibility factor is found to be 0.940.Find the pressure of the gas. [4%] (F) Estimate the van der Waal's constant a (in atm*L^2*mol^(-2) ) of O2.[5%] 3. Consider the ocean to be 0.500M NaCl solution. Answer the following questions. Assume complete dissociation of NaCl; density=1.00g/ml for all aqueous solutions; Na=23.0; Cl=35.5. (A) Calculate the osmotic pressure of the ocean at 30.0*C. [3%] (B) Indicate the direction of water flow when seawater is separated from pure water by a semipermeable membrane. [3%] (C) Estimate the minimum work required to transfer 5.00 mol of water from seawater to pure water through a semipermeable membrane at 30.0*C? [4%] (D) If the vapor pressure of water at 20.0*C is 17.8 torr, what is the vapor pressure at 30*C? The molar enthalpy of vaporation for water is 40.0kJ*mol^(-1). [5%] (E) Find the vapor pressure of seawater at 30.0*C. [5%] (F) If 6.00g of a non-dissociating substance X dissolved in 94.0g of water is isotonic (i.e.,same osmotic pressure) to the seawater, find the molar mass of X? [5%] 4. The thermodynamic properties for white tin and gray tin at 1 atm are given below: substance ΔHf* (KJ*mol^(-1)) S* (J*K^(-1)*mole^(-1)) Density (g*cm^(-3)) ----------------------------------------------------------------------------- white tin 0.00 51.5 7.31 gray tin -2.12 44.1 5.75 Answer the following questions. (Sn=118.7) (A) Estimate the phase transition temperature (in *C) for gray and white tin. [5%] (B) What is the stable form of tin at low temperatures? Explain. [4%] (C) What is the stable form of tin at high pressures? Explain. [4%] (D) Calculate the work involved in the transition of 10.1 mol white tin to gray tin at the phase transition temperature and 1 atm. [6%] (E) The slope of the phase transition curve is given by dP/dT=ΔS*/ΔV. Estimate the phase transition temperature for white tin --> gray tin at 100 atm. Assume ΔS* and ΔV are independent of T and P. [6%] ====================================== 以下 附上教授提供的解答! 1. (A) Pt = +4, d6 for cation; Pt = +2; d8 for anion (B) dicyanatobis(ethylenediamine)platinum(IV) dichlorodicyanatoplatinate(II) (C) 略 (D) 略 (E) 略 (F) -12/8Δo 2. (A) 446 m*s^(-1) (B) 1.01*10^(-7) m (C) d=0.301 nm (D) 0.0344 L*mol^(-1) (E) P2=18.8 atm (F) a = 1.40 atm*L^2*mol^(-2) 3. (A) 24.9 atm (B) pure water => sea water (C) 227 J (D) 30.6 torr (E) 30.0 torr (F) 60 g/mol 4. (A) 13.2*C (B) white => gray . ΔH*=-2.20 kJ/mol low T favors the exothermic process ; gray tin is the stable form at low T (C) high P favors the dense materials gray tin is the stable form at high P (D) -4.46J (E) 7.2*C --

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