【GR1727】 The Solution for GRE Chemistry Practice Test [41-60]

The Solution for GRE Chemistry Practice Test [41-60]  

 

추천글 : 【GRE】 Solution for GRE Chemistry Practice Test 

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41. Given the standard molar entropies listed below, the standard reaction entropy, ΔS°, in J K^-1 mol^-1, for the decomposition of calcium carbonate into calcium oxide and carbon dioxide is  

 

 

⑴ answer: E

⑵ CaCO₃ (s) → CaO(s) + CO₂(g) 

 

 

42. The Rydberg equation given below accurately predicts the UV-visible emission spectrum of the hydrogen atom. A form of the Rydberg equation may also be used to predict the UV-visible emission for all of the following EXCEPT

 

 

⑴ answer: A

⑵ Only species with a single electron can be applied to the equation.

 

43. Phtalic acid, (COOH)C₆H₄(COOH), is a weak, diprotic acid with dissociation constant below. The pH of an aqueous solution of potassium acid phthalate, (COOH)C₆H₄(COO^-K⁺), is closest to

 

 

⑴ answer: D

⑵ ( pK_a1 + pK_a2 ) / 2

 

 

44. Which of the following is true for Br₂ at standard temperature and pressure?

 

 

⑴ answer: B

⑵ color organic materials : Br₂, FeCl₃, AgNO₃, KMnO₄, Cr, NH₄Cl, etc 

 

 

45. On the basis of oxidation-reduction potential, which of the following is most likely to occur?

 

 

⑴ answer: B

⑵ ionization tendency: K＞Ca＞Na＞Mg＞Al＞Zn＞Fe＞Ni＞Sn＞Pb＞H＞Cu＞Hg＞Ag＞Pt＞Au

⑶ In (E), Ca(s) will react with H₂O.

 

 

46. Cobalt-60 is used in the radiation therapy of cancer and can be produced by bombardment of cobalt-59 with which of the following?

 

 

⑴ answer: A 

 

 

47. Which of the following are the products of the reaction shown below?

 

 

⑴ answer: E

⑵ acid-catalyzed anhydride hydration reaction 

 

 

48. What is the product of the reaction shown below for para-cresol?

 

 

⑴ answer: A

⑵ step 1. Me-Ph-OH → Me-Ph-O^-Na⁺

⑶ step 2. alkyl halide S_N2 reaction 

 

 

49. At 25 ℃, the maximum amound of PbI₂ that can be dissolved in 1.00 L of pure water is 1.0 mmol. Assuming complete dissociation, the solubility product, K_sp, for lead iodide at 25 ℃ is 

 

 

⑴ answer: E 

⑵ K_sp = [ Pb²⁺ ] × [ I^- ]² = 10^-3 × (2 × 10^-3)² = 4 × 10^-9 

 

 

50. Which of the following must be true if the wavefunction ψ(x) is normalized? 

 

 

⑴ answer: D

 

 

51. If ψ(r) is the wavefunction for a 1s electron, the average distance from the nucleus for the electron is equal to 

 

 

⑴ answer: E

 

 

52. Which of the following experimental observations were explained by Planck's quantum theory?

 

 

⑴ answer: A

⑵ black body radiation curve 

 

 

53. The +1 oxidation state is more stable than the +3 oxidation state for which group 13 element? 

 

 

⑴ answer: E

⑵ It is due to f orbital.

 

 

54. The anhydride of Ba(OH)₂ is 

 

 

⑴ answer: E

⑵ Ba(OH)₂ - H₂O = BaO 

 

 

55. A 0.217 g sample of HgO (molar mass = 217 g) reacts with excess iodide ions according to the reaction shown below. Titration of the resulting solution requires how many mL of 0.10 M HCl to reach equivalence point?

 

 

⑴ answer: C

⑵ 0.217 g ÷ 217 g / mol × 2 = 0.10 M × x mL × 1L / 1000 mL → x = 20 mL

 

 

56. The Hamiltonian operator for a particle in a one-dimensional box, whose potential is zero inside the box and infinite outside the box, is

 

 

⑴ answer: A 

⑵ Hamiltonian operator : It represents energy terms. 

⑶ condition 1. one-dimensional : 🄓 and 🄔 are inappropriate.

⑷ condition 2. Schrödinger equation : 🄐 is chosen.

 

 

 

57. The normal modes of a carbon dioxide molecule that are infrared-active include which of the following?

Ⅰ. Bending

Ⅱ. Symmetric stretching

Ⅲ. Asymmetric stretching

 

 

⑴ answer: D 

 

 

58. Which of the following types of spectroscopy is a light-scattering technique?

 

 

⑴ answer: C

 

 

59. When a certain metal is irradiated with radiation of frequency 5.5 × 1014 s-1, electrons are ejected. If the work function of the metal is 2.9 × 10-19 J, which of the following expresses the kinetic energy (in joules) of the ejected electrons?

 

 

⑴ answer: A 

 

 

60. The product of the reaction shown below is produced via which of the following intermediates?

 

 

⑴ answer: E

⑵ intramolecular aldol reaction 

 

 

 입력: 2022.03.03 23:35