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110年 - 110 國立臺灣大學_碩士班招生考試_部分系所:普通化學#100705

科目：研究所、轉學考(插大)◆普通化學 | 年份：110年 | 選擇題數：0 | 申論題數：19

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所屬科目：研究所、轉學考(插大)◆普通化學

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申論題 (19)

(a) (5 marks). From elemental analysis, it is found that MSG contains the following mass distribution: carbon (35.00%), hydrogen (4.69%), nitrogen (8.16%), oxygen (38.57%), sodium (13.52%). Find the empirical formula of MSG [Molar mass information (g/mol): carbon 12.01, hydrogen 1.01, nitrogen 14.01, oxygen 16.00, sodium 23.00]
(b) (5 marks) By mass spectrometry, we find that MSG has a molar mass of 187.127 g/mol. Deduce the molecular formula of MSG. Explain why the result of mass spectrometry is somewhat different from what you expected from your moleculu formula.
(c) (5 marks) By infrared spectros oscopy, we can show that MSG contains carboxylate and amine groups. Write down three different structural formulae possible for MSG
(d) (5 marks) Describe two experimental methods to determine the correct structural formula for MSG.
(a) (5 marks) For an aqueous solution containing 3.59 mM of SO2, what is the ration of SO2 in ppm? [Molar mass of sulfur is 32.065 g/mol]
(b)(5 marks) Explain the physical origin of the octet rule using the concepts in quantum mechanics. (You just need to consider the outermost shell of Ne as an example].

(c) (5 marks) Explain the following trend of electron affinity for halogens:6127233cec182.jpg

(d) (5 marks) Draw the molecular orbital (MO) diagram of O2. Do you think the bond length of612723700a25b.jpg is longer, shorter, or identical to O2? Explain your answer.

(a) (5 marks) Determine the neutral pH for water at 100℃. Explain whether a pH value of 6.5 at 100℃ is acidic or alkaline.

(b) (10 marks) Calculate the pH of a 0.050 M aqueous solution of alanine. Hints: the structural formula of alanine in water is+H3N-CH(R)-COO-, where R = CH3.
  612723fc055fa.jpg
(c) (5 marks) Explain whether the pKn of alanine is smaller or larger in blood than in pure water.

(a) (5 marks) The major inorganic species in shark teeth is known as fluorapatite (FAp) with the formula of Cas(PO4)3F. If some of the "PO4" ions are substituted by carbonate ions, will the amount of6127243fba50e.jpg ions per FAp unit increase, decrease, or remain the same? Explain why.
(b) (5 marks) Consider the substituted FAp compound with a formula of Ca,(PO4)3-(CO3)xF. Experimentally it is found that the ratio of Ca/P = 1.70. Determine x and y.
(a) (3 marks) What additions must you make to the cell for it to generate a standard
(b) (I mark) Which electrode functions as the cathode?

(c) (6 marks) Calculate the standard enf, calculate △G° at 298.0 K, and calculate the equilibrium constant 612724f3466e1.jpgK for this reaction.
(a) (10 marks) HEPES is known to form zwitterionic ions at neutral pH. Write down the zwitterionic form of HEPES and provide two chemical reasons to justify your answer.

(b) (5 marks) HEPES has 6127254f42fb7.jpg. Write down the chemical reaction relevant to the buffering capacity of HEPES.
(c) (5 marks) HEPES is comn mercially available as a sodium salt. After solubilizing some sodium HEPES in water, should you add acid or base to prepare a buffer at 7.40?