8. For the transition of n = 3 →n = 2 to occur in the hydrogen atom, the wavelength of the resulting emitted light is _____ nm.
(A) 121.6
(B) 656.7
(C) 1876
(D) 486.4
(E) 48.64

4. Consider three identical flasks filled with different gases: Flask A, CO at 760 torr and 0°C； Flask B, N2 at 250 torr and 0°C； Flask C, H2 at 100 torr and 0°C. Which one of the following statements is consistent with the conditions described above? (A) Ranking the gases in order of increasing average kinetic energy: Flask A＞ Flask B ＞ Flask C (B) Ranking the gases in order of increasing average velocity: Flask A ＞ Flask B ＞ Flask C (C) Ranking the gases in order of increasing average velocity: Flask B ＞ Flask A ＞ Flask C (D) Ranking the gases in order of increasing average kinetic energy: Flask A = Flask B = Flask C (E) Ranking the gases in order of increasing average kinetic : Flask A ＜ Flask B ＜ Flask C

5. At elevated temperatures, sodium chlorate decomposes to produce sodium chloride and oxygen gas. A 0.8765-g sample of impure sodium chlorate was heated until the production of oxygen gas ceased. The oxygen gas collected over water occupied 57.2 mL at a temperature of 22°C and a pressure of 734 torr. At 22°C the vapor pressure of water is 19.8 torr. The mass percentage of sodium chlorate in the original sample is_____. (A) 46.5% (B) 18.0% (C) 23.3% (D) 76.7% (E) 53.5%

6. Consider the dissolution of CaCl2: CaCl2(s)→Ca2+(aq) +2Cl ̄(aq), △H = -81.5 kJ. An 11.0-g sample of CaCl2 is dissolved in 125 g water, with both substances at 25°C. Assuming no heat loss to the surroundings and assuming the solution has a specific heat capacity of 4.18 J/°C g, the final temperature of the solution is _____°C. (A) 39.2(B) 26.8(C) 14.2(D) 23.7(E) 30.0

7. Which one of the following statements is incorrect? (A) An unknown nonmetal element with a valence electron configuration of ns2np4 has a smaller radius than barium. (B) The set of quantum numbers, n = 4, l = 3, ml = 4 is not allowed in the hydrogen atom. (C) A certain oxygen atom with the electron configuration of 1s22s22px22py2 has no unpaired electrons. (D) The order of increasing first ionization energy among K, Br, Ni is: Br ＜ Ni ＜K (E) (Kr)5s24d105p5 is the expected ground-state electron configuration for the element with one unpaired 5p electron that forms a covalent compound with fluorine.

9. Which one of the following statements is correct? (A) SO4 is more energetically stable than XeO4. (B) The order of increasing ionization energy in CI+ ＞ CI ＞ Se ＞ Se- is valid. (C) SeO3 has a T shape structure. (D) N2O is a nonpolar molecule. (E) The AsF5 molecule has a square pyramidal structure.

10. Consider the following reaction: H2C=CH2(g) + F2(g)→H2FC-CFH2(g), △H = -549 kJ. Please estimate the carbon-fluorine bond energy to be _____ kJ/mol given that the C-C bond energy is 347 kJ/mol, the C=C bond energy is 614 kJ/mol, and the F-F bond energy is 154 kJ/mol. (A) 239 (B)-184(C) -92(D) -327(E) 485

11. Consider three molecules: A, B, and C. Molecule A has a hybridization of sp3. Molecule B has two more effective pairs (electron pairs around the central atom) than molecule A. Molecule C consists of two σ bonds and two π bonds. Thus, which one of the following statements relating to A, B and C is incorrect? (A) Molecule A has a tetrahedral arrangement of electron pairs. (B) Molecule B has a square planar structure. (C) Molecule B has a bond angle of 109.5°. (D) The structure of HCN is similar to C. (E) Molecule C is consistent with a linear arrangement of electron pairs exhibiting sp hybridization.

12. A certain metal fluoride crystalizes in such a way that the fluoride ions occupy simple cubic lattice sites, while the metal ions occupy the body centers of half the cubes. The formula of the metal fluoride is thus_____. (A) MF (B) MF3 (C) MF5 (D) MF4 (E) MF2

13. The solubility of CaCl2 in cold water is 74.5 g per 100.0 g water. Assuming i = 2.6 for CaCl2, the freezing point for a saturated solution of CaCl2 will be _____°C. (A)0 (B) -0.32 (C) -13 (D) -32 (E) -37.4

14.For the reaction A →products, successive half-lives are observed to be 10.0, 20.0 and 40.0 min for an experiment in which [A]0 = 0.10 M. Based on the information, the concentration of A after 30 min of the reaction is ＿ M (A) 0.008 (B) 0.30 (C) 0.025 (D) 0.011 (E) 0.0021