1. The average distance of an electron in a hydrogen atom from the nucleus is indicated by the quantum number

(A) n
(B) m_l
(C) l
(D) m_s

2. "Wood alcohol" (methyl alcohol or methanol), CH₄O, is toxic and is used as a denaturant in industrial grain alcohol and as a fuel. A satisfactory Lewis structure for this compound is

3. In the SiH₄ molecule, the Si atomic orbitals used in forming covalent bonds are best described as

(A) one s and three p atomic orbitals
(B) four sp³ hybrid orbitals
(C) four d²sp³ hybrid orbitals
(D) three sp² orbitals and one p orbital

4. The triple bond in the N₂ molecule can be described as

(A) two bonding and one antibonding sigma bonds
(B) three sigma bonds
(C) one sigma and two pi bonds
(D) two bonding and one antibonding pi bonds

5. Which one of the following is not the expected geometry of the indicated molecule or ion?

(A) CCl₄ - regular tetrahedron
(B) BeCl₂ - linear
(C) SO₃ - triangular pyramid
(D) CH₂O - trigonal planar

6. A 0.10 molal aqueous solution of HF shows a freezing point of -0.198 °C. What is the percent dissociation of HF into ions in this solution? (K_f = 1.86 for water)

(A) 6.4%
(B) 10%
(C) 20%
(D) 98%

7. Which one of these solid substances has a crystal structure containing separate discrete molecules?

(A) Dry ice
(B) Graphite
(C) Quartz
(D) Silver bromide

8. A solution of a non-electrolyte, x, contains 84 grams of x per kilogram of water and freezes at -1.46°C. What is the molecular weight of x? (K_f = 1.86)

(A) 84 x 1.86 x 1.46 = 222 g/mol
(B) 84 x (1.86 / 1.46) = 107 g/mol
(C) 84 x (1.46 / 1.86) = 66 g/mol
(D) 1.46 x (1.86 / 84) = 0.032 g/mol

9. A 1.20 liter sample is drawn from a bottle labeled "86.0% by weight H₂SO₄, density 1.787 g/mL". What is the molarity of the sample?

(A) 8.78 M
(B) 10.5 M
(C) 15.7 M
(D) 18.2 M

10. Which substance is most soluble in water?

(A) C₆H₆
(B) CH₃OH
(C) CO₂
(D) CH₄

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