4. Which of the following is a valid Fischer projection for D-(+)-xylose? (Image of D-(+)-xylose and 5 Fischer projections A-E)

(A)
(B)
(C)
(D)
(E)

1. What is the bond angle between the two N,N-dimethyl groups of N,N-dimethylpropionamide? (A) 90° (B) 107° (C) 109.5° (D) 120° (E) 180°

2. Which of the following compounds possess the most acidic C-H bond (as highlighted). (Image of 5 compounds A-E)(A)(B)(C)(D)(E)

3. Determine the identity of the compound based on 13C NMR shown below. (Image of 13C NMR spectrum and 5 compounds A-E)(A) (B)(C)(D)(E)

5. Which of the following Newman projections represents the lowest energy conformation of (S)-3-chloro-2,2-dimethylpentane? (Image of 5 Newman projections A-E)(A)(B)(C)(D)(E) 

Part II: Written Questions (Total: 40 points) Note: 6. The electron configuration of Mn is (A) [Ar]4s03d⁷ (B) [Ar]4s¹3d⁵ (C) [Ar]4s¹3d⁶ (D) [Ar]4s²3d⁵ (E) [Ar]4s²3d6

7. Which of the following n' → n transitions in the emission spectrum of atomic hydrogen belong to the Balmer series? (A) 5→4 (B) 5→3 (C) 4→3 (D) 3→2 (E) 4→1

8. Which of the following water solution is more acidic? (A) 1M HCl (B) 1M HNO₃ (C) 1M H₂SO₄ (D) 1M CH₃COOH (E) 1M NaOH

9. Regarding "ionic liquid", which of the following is   incorrect  ? (A) it is a green solvent beneficial to the environment (B) it is a kind of salt (C) its melting point is generally below room temperature (D) its structure has a significantly low symmetry (E) it is highly stable with negligible vapor pressure

10. There are three types of cubic unit cells, including simple cubic (SC), face-centered cubic (FCC), and body-centered cubic (BCC). Which of the following is   correct  ? (A) BCC has 4 atoms per unit cell (B) FCC has the largest unit cell (C) The coordination number of SC is 8 (D) FCC is alternatively called hexagonal close-packed structure (E) In BCC, the atomic packing factor is 0.68

11. Which of the following statements is   correct  ? (A) The conductivity of metal raises with the increase of temperature (B) the addition of boron into the silicon forms the n-type semiconductor (C) the decrease of temperature enhances the conductivity of semiconductors (D) because both valence band and conduction band are full, the electrons can not move so that the insulator is not conductive (E) because all the valence electrons of carbon form the covalent bonds, the diamond is not conductive