110年 - 110 高雄醫學大學_學生轉系考：普通化學#113615

1. A 25.00-g sample of a solid is placed in a graduated cylinder, and then the cylinder is filled to the 50.0-mL mark with benzene. The mass of benzene and solid together is 58.80 g. Assuming that the solid is insoluble in benzene and that the density of benzene is 0.880 g/cm³, please calculate the density of the solid to be _____g/dm³.(A) 2160(B) 2200(C) 2.16(D) 2.2(E) 2

3. Ten tablets with a total mass of 0.5894 g contained saccharin (C₇H₅NO₃S) and were dissolved in water. The saccharin was oxidized to convert all the sulfur to sulfate ion, which was precipitated by adding an excess of barium chloride solution. The mass of barium sulfate obtained was 0.5032 g. The average mass percent of saccharin in the tablets is thus_____. (A) 33.00% (B) 0.052% (C) 53.10% (D) 95.95% (E) 67.00%

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

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

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

15. Suppose the reaction system 2HI(g)⇌H2(g) + I2(g) has already reached equilibrium. Which of the following statements correctly predict the effect of each change on the equilibrium position? (A) Additional H₂(g) added to the system will shift to the right to obtain the equilibrium. (B) As an exothermic reaction, the system will shift to the right to attain the equilibrium when increasing the system temperature. (C) When iodine gas is removed, the system will shift to the left to achieve the equilibrium. (D) Addition of argon gas into the reaction system will shift to the right to achieve the equilibrium. (E) When volume of the reaction container is doubled, the change will have no effects on its equilibrium.

16. In a 0.10-M aqueous solution of pyridine (Kь = 1.7 × 10^-9), the percentage of pyridine (C₅H₅N) that forms pyridinium ion, C₅H₅NH⁺, is _____%. (A) 0.013 (B) 6.4 (C) 4.2 (D) 1.3 (E) 5.5

17. Consider the titration of 40.0 mL of 0.200 M HCIO₄ by 0.100 M KOH. After adding 10.0 mL of the KOH solution, the pH of the resulting solution is _____. (A) 1.15 (B) 7.00 (C) 2.72 (D) 0.85 (E) 4.26

20. For the reaction at 800 K: N₂(g) + 3F₂(g)→2NF₃(g), an equilibrium mixture contains the partial pressures of P_(nitrogen) = 0.021 atm, P_(fluorine) = 0.063 atm, and P_{(nitrogen trifluoride)} = 0.48 atm. The △G° for the reaction at 527°C is thus _____kJ/mol. (A) 17 (B)-50 (C) 50 (D)-17 (E)-71

21. Which one of the following statements is correct? (A) The value of S° for N₂O at 0 K is greater than that for He at 10 K. (B) At 1 atm and 25°C, the value of S° for He(g) is greater than that for N₂O(g). (C) The sign of S° for the reaction of 2H₂S(g) + SO₂(g) → 3S_rhombic(s) + 2H₂O(g) is negative. (D) The sign of S° for the reaction of 2SO₃(g) → 2SO₂(g) + O₂(g) is negative. (E) The sign of S° for the reaction of Fe₂O₃(s) + 3H₂(g) → 2Fe(s) + 3H₂O(g) is only positive.

22. When electrolyzing a sodium chloride solution at 50°C and 2.50 atm, the volume of _____ L H₂(g) is acquired in addition of the production of 257 L Cl₂(g) with both volumes measured in the same time. (A) 257(B) 128.5(C) 85.7(D) 514(E) 771