課程名稱︰普通化學丙
課程性質︰必帶
課程教師︰林英智
開課學院：醫學院
開課系所︰藥學系,醫技系
考試時間︰2006/11/10 10:20~12:10
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
General Chemistry -- Mid Term 1 (2006)
1.Calculate the impact rate on a 2.00-cm^2 section of a vessel containing
oxygen gas (molecular mass:32 g/mol) at a pressure of 0.1 atm and 77℃.
2.A compound containing only C, H, and N yields the following data.
i. Complete combustion of 35.0 mg of the compound produced 33.5 mg of CO2
and 41.1 mg of H2O.
ii. A 65.2-mg sample of the compound was analyzed for nitrogen by the Dumas
method, giving 35.6 mL of N2 at 740. torr and 25℃.
*Dumas method---The compound in question is reacted by passge over hot
CuO(s):
Compound --[ Hot,CuO(s) ]--> N2(g) + CO2(g) + H2O(g)
iii. The effusion rate of the compound as a gas was measured and found to
be 24.6 mL/min. The effusion rate of argon gas, under identical
conditions, is 26.4 mL/min. (atomic mass of Ar is 39.95 g/mol)
What is the formula of the compound?
3.Calculate the fractions of ascorbic acid (vitamin C, H2C6H6O6), HC6H6O6¯and
(C6H6O6)2¯at pH 9.00. (ascorbic, Ka1=7.9*10^-5, Ka2=1.6*10^-12)
4.Calculate the pH of (a) 0.100M solution of NH4CN.
(b) 1.0*10^-4M solution of HCN
(Ka(NH4+) = 5.6*10^-10, Ka(HCN) = 6.2*10^-10)
5.Calculate the change in entropy that occurs when a sample containing 2.00
mol of water is heated from 50℃ to 150℃ at 1 atm pressure. The molar heat
capacities for H2O(l) and H2O(g) are 75.3J/(K˙mol) and 36.4J/(K˙mol),
respectively, and the enthalpy of vaporization for water is 40.7kJ/mol at
100℃.
6.Consider a sample containing 1.00 mol of a monatomic, ideal gas at 57.0℃
and an initial pressure of 10.0 atm. Suppose the external pressure is
lowered to 0.5 atm in a reversible adiabatic manner. Calculate the final
temperature and volume of the gas sample and compute the work for the
process.
7.Consider 1.00 mol of an ideal gas at 25℃.
(a) Calculate q, w, ΔE, ΔS, ΔH and ΔG for the expansion of this gas
isothermally and irreversibly from 2.45*10^-2 atm to 2.45*10^-3 atm in
one step.
(b) Calculate q, w, ΔE, ΔS, ΔH and ΔG for the same change of pressure
as in part (a) but performed isothermally and reversibly.
(c) Construct the PV diagrams for the processes described in parts (a) and
(b).
8.If 1.000 mol of an ideal gas were confined to 22.41 L at 0.0℃, it would
exert a pressure of 1.000 atm. Use the van der Walls equation and the
constants (a = 6.49 L^2-atm/mol^2, b = 0.0562 L/mol) to estimate the
pressure exerted by 1.000 mol of Cl2(g) in 22.41 L at 0.0℃.
9.(a) Explain why H3PO3 is diprotic and not triprotic acid.
(b) A 25.0-mL sample of a solution of H3PO3 is titrated with 0.102 M NaOH.
It requires 23.3 mL of NaOH to neutralize both acidic protons. What is
molarity of the H3PO3 solution?
(c) This solution has a pH of 1.59. Calculate the percent ionization and
Ka1 for H3PO3, assuming that Ka1>>Ka2.
(d) How does the osmotic pressure(滲透壓) of a 0.050 M solution of HCl
compare with that of a 0.050 M solution of H3PO3? Explain.
10.The normal boiling point is the temperature at which a pure
liquid is in equilibrium with its vapor at a pressure of 1 atm.
(a) Write the chemical equation that defines the normal boiling point of
liquid carbon tetrachloride, CCl4(l).
(b) What is the value of ΔG° for the equilibrium in part (a)?
(c) Use thermdynamic data of :
CCl4(g), [ΔH°(f) = -106.7kJ/mol, S° =309.4J/mol˙K)
CCl4(l), [ΔH°(f) = -139.3kJ/mol, S =214.4J/mol˙K)
to estimate the normal boiling point of CCl4.
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※ 編輯: ryo2006 來自: 140.112.250.56 (11/11 00:01)