课程名称︰物理化学上 课程性质︰必修 课程教师︰苏志明 开课学院：生农学院 开课系所︰农业化学系 考试日期（年月日）︰2008 10 23 考试时限（分钟）：125 是否需发放奖励金：是 （如未明确表示，则不予发放） 试题 : 1.Caculate the change in entropy at constant P when 1 mol of liquid water at 100℃ is brought in contact with 1 mol of liquid water at 0℃. Assume that the constant pressureheat capacity of liquid water is independent of temperature and is equal to 75J/mol*K. In this process no heat is lost to the surroundings. 2.If a spark is applied to a mixture of H2(g) and O2(g), an explosion occurs and water is formed. The gaseous water is cooled to 100℃. Caculate the entropy change when 2 mol of gaseous H2O is formed at 100℃ and 1 atm from H2(g) and O2(g) at the same temperature and each at a partial pressure of 1 atm. 3.For 1 mole of ideal gas undergoing an adiabatic expansion form the initial state of (P1,V1) to a final state of (P2,V2), derive the equation relating these two states. 4.The shells of marine organisms contain CaCO3 largely in the crystalline form known as calcite. There is a second crystalline form of CaCO3 known as aragonite. (a)Based on the thermodynamic and physical properties given in the following table for these two crystalline forms, would you expect calcite in nature to convert spontaneously to aragonite given sufficient time? Justify your answer. (b)Will the conversion proposed in part (a) be favored or opposed by increa- sing the pressure? Explain. (c)What pressure should be just sufficient to make this conversion spontaneous at 25℃? (d)Will increasing the temperature favor the conversion? Explain. Properties at 298K calcite aragonite ΔH(kJ/mol) -1206.87 -1207.04 ΔG(kJ/mol) -1128.76 -1127.71 S(J/K*mol) 92.88 88.70 Cp(J/K*mol) 81.88 81.25 density(g/cm^3) 2.710 2.930 5.Consider 1 mole of carbon dioxide at 25℃. (a)Assuming that the gas follows the equation of ideal gas, calculate the work, heat, internal energy change, and enthalpy change if the gas is expanded reversibly and isothermally from an initial volume of 5L to a volume of 10L. (b)The carbon dioxide gas actually follows the van der Waals equation with the van der Waals constants a=3.6(L^2*atm/mol^2) and b=0.043(L/mol). Cal- culate the thermodynamic quantities listed in (a) if the gas also assume the same expansion process. 6.Consider the reaction in which 1 mol of aspartic acid(s) is converted to alanine(s) and CO2(g) at 25℃ and 1 atm pressure. The balanced reaction is H2NCH(CH2COOH)COOH(s) → H2NCH(CH3)COOH(s) + CO2(g) (a)How much heat is evolved or absorbed? (b)Write a cycle you could use to calculated the heat effect for the reaction at 50℃. State what properties of molecules you would need to know and what equations you would use to calculate the answer. 7.A reaction that is representative of those in the glycolytic pathway is the catabolism of glucose by complete oxidation to carbon dioxide and water: C6H12O2(s) + 6 O2(g) → 6 CO2(g) + 6 H2O(l) Calculate the ΔH(298) for the glucose oxidation. Some equations and thermodynamic data: (a) H = E + PV (b) dS = dq(rev)/T (c) dG(rev. path) = VdP - SdT (d) ∫(1/ax+b)dx = (1/a)㏑|ax+b|+c 标准反应热等资料详阅课本。 --

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