課程名稱︰普通化學甲上 班次01(化學系)
課程性質︰必修
課程教師︰牟中原 陳振中合開
開課系所︰化學系
考試時間︰2004.12.3
試題 :
九十三學年度 化學系 普通化學甲 第二次期中考
1. The Ksp of hydroxypatite, Ca5(PO4)3OH, is 6.8X10^-37. Calculate the
solubility of hydroxypatite in pure water in moles per liter. How is the
solubility of hydroxypatite affected by adding acid? When hydroxypatite is
treated with fluride, the mineral flourapatite, Ca5(PO4)3F, forms. The Ksp
of this substance is 1X10^-60. Calculate the solubility of fluorapatite in
water. How do these calculations provide a reason for the fluoridation of
drinking water? 15%
2. Consider a sample containing 2.00mol of a monatomic ideal gas that undergoes
the following changes:
Pa=10.0atm 1 Pb=10.0atm 2 Pc=20.0atm 3 Pd=20.0atm
Va=10.0L → Vb=5.0L → Vc=5.0L → Vd=25.0L
For each step, assume that the external pressure is constant and equals the
final pressure of the gas for that step. Calculate q, w,and △H for each
step and for the overall change from state A to state D. 15%
3. When water is supercooled, it freezes at a temperature below 0.0℃. If 10.9
kJ of heat is released when 2.00mol of supercooled water at -15.0℃ freezes,
calculate the molar enthalpy of fusion for ice at 0.0℃ and 1 atm. Assume
the molar heat capacities for H2O(s) and H2O(l) are 37.5J/K˙mol and 75.3
J/K˙mol, respectively, and are temperature independent. 15%
4. Calculate the total entropy change when a 2.00 kg mass at 300K falls freely
a distance of 25.0m into a heat bath at 300K. 10%
5. Which of the following pairs has greater entropy per mol?
(a) Acetone and methane (all in gas phase)
(b) Chlorinf and fluorine (all in gas phase)
(c) Water and ice at 273K
(d) Methane and ethane (all in gas phase)
(e) Diamond and graphite 10%
6. Hydrogen for use in the Haber-Bosch process for ammonia synthesis is
generated from natural gas by the reaction
CH4(g) + H2O(g) → CO(g) + 3H2(g)
(a) Calculate △G°for this reaction at 25℃.
(b) Calculate Ksp for at 25℃.
(c) Is the reaction product-favored under standard conditions? If not, at
what temperature will it become so?
(d) Estimate Kc for the reaction at 1000K. 20%
┌───────┬────┬────┬────┬────┐
│ │ CH4(g) │ H2O(g)│ CO(g) │ H2(g) │
├───────┼────┼────┼────┼────┤
│△G°f(kJ/mol)│ -50.22 │-228.572│-137.168│ 0 │
├───────┼────┼────┼────┼────┤
│△H°f(kJ/mol)│ -74.81 │-241.818│-110.525│ 0 │
├───────┼────┼────┼────┼────┤
│S°(J/mol˙K) │186.264 │188.825 │197.674 │130.684 │
└───────┴────┴────┴────┴────┘
7. The molar heat capacity of H2O(g), at constant P, is given by
Cp = 30.54 + 0.01T (J/mol˙K)
Calculate △S, △H, △E when 100g of H2O at 373K, 1.00atm is heated to 473K,
1.00atm. Assume ideal gas behavior. 15%
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