所屬科目:研究所、轉學考(插大)◆普通化學
1. How many significant figures should be reported for the answer to the following calculation? (1.0045 – 0.0013) (A) 1 (B) 2 (C) 3 (D) 4 (E) 5
2. Which of these atoms does not obey the octet rule? (A) S in SF4 (B) Si in SiCl4 (C) P in PC13 (D) N in N2 (E) None of the previous answers
3. In which of these molecules does carbon have an oxidation state of 0? (A) CO2 (B) H2CO (C) CH4 (D) HCCl3 (E) None of the previous answers
4. For the reaction HCONH2(g) = NH3(g) + CO(g), = 4.84 at 400 K. If AH° for this reaction is 29 kJ/mol, what is the approximate at 300 K? (A)(B) (C) 27 (D) 89 (E) 0.26
5. Consider a sample of 1 mol Kr (g) at a given temperature contained in a given volume. Which of the following statements are false? (A) The entropy of 1 mol Kr (g) is less than that of 1 mol Kr (s) at the same temperature. (B) The entropy of the sample is less than that of a 1 mol sample C4H10 (g) at the same temperature, contained in the same volume. (C) The entropy of the sample increases when the temperature is doubled. (D) The entropy of the sample decreases when the volume of the container is reduced (assuming the same initial and final temperatures). (E) Rotational and vibrational motions do not contribute to the overall entropy of the sample.
6. What is the characteristic wavelength of an electron with a kinetic energy of 9.00 x J? (A) 444 nm (B) 369 pm (C) 590 pm (D) 16.4 pm (E) 0.198 pm
7. Which of the following statements is true? (A) Molecules containing polar bonds must be polar molecules. (B) Hydrogen bonding is generally stronger than ionic bonding. (C) London dispersion forces are only present between non-polar molecules. (D) Resonance structures of a molecule interchange in rapid, reversible, equilibrium (E) Liquid methanol (CH3OH) exhibits intermolecular hydrogen bonding interactions.
8. Consider a vessel containing the following exothermic reaction at equilibrium:
2 SO2 (g) + O2 (g) ⇌ 2 SO3 (g)
Which changes would increase the amount of O2 (g) present? (A) Cooling the reaction (B) Doubling the volume of the reaction vessel (C) Adding SO2 (g) (D) Adding a catalyst (E) None of the previous answers.
9. Identify the orbital in the illustration: (A) 3d (B) 3p (C) 4d (D) 4p (E) 5d
10. Consider the following salts and choose the true statement:
(A) NiCO3 has the greatest molar solubility. (B) NiCO3 has a greater solubilty in g/L than PbF2. (C) PbI2 has a greater solubilty in g/L than NiCO3. (D) Addition of iodide to a solution of PbI2 will result in a decrease of its . (E) None of the above statements are true.
11. Label the functional group(s) present in the following molecule in English :
12. Phenol (C6H5OH) and n-hexanol are both alcohols. However, phenol is much more acidic than hexanol. Explain.
13.Combustion analysis of 20.00 mg of an unknown compound containing only C, H, and O gives 49.23 mg CO2 and 12.96 mg H2O. The compound has a molecular mass of 250.3 g/mol. What is the probable molecular formula of the compound?
14. Ascorbic acid (H2C6H6O6) is a diprotic acid with and (A) What is the pH of a solution of 350.0 mg ascorbic acid in 500.0 mL water? Show your calculations. (5 pts) (B) Suppose 150.0 mL of 0.01000 M NaOH (aq) was added to the solution from (A). What would the pH of the resulting solution be? Show your calculations.
15. Radium-226 is a radioactive isotope that decays to form Radon-222 and an alpha particl(E) This process follows first-order kinetics, and the half-life of Radium-226 is 1600 years. Given a sample of 5.00 g of Radium-226, how many moles of Radon-222 would be present in the sample after two years?
16. A galvanic cell is made based on the following reaction:
With relevant half reactions:
If = 0.10 M, = 0.10 M, = 1.00 M, and Ecell = 3.02 V at 298 K, what is the pH of the cathode compartment?