資訊推薦

• 56. A certain bacterial mRNA is known to represent only one gene and to contain about 800 nucleotide
• 57. Which of the following statements about the polymerase chain reaction (PCR) is false?(A) DNA amp
• 58. Which of the following is not true of the citric acid cycle?(A) All enzymes of the cycle are loc
• 59. Steroid receptor proteins are a class of closely-related DNA binding proteins. These steroid rec
• 60. Which of the following sequences is most likely to contain a termination signal for procaryotic
• 2. Which one of the following statements is incorrect?(A) Sodium arsenate has its formulas of Na3AsO
• 3. Ten tablets with a total mass of 0.5894 g contained saccharin (C7H5NO3S) and were dissolved in wa
• 4. Consider three identical flasks filled with different gases: Flask A, CO at 760 torr and 0°C； Fla
• 5. At elevated temperatures, sodium chlorate decomposes to produce sodium chloride and oxygen gas. A
• 6. Consider the dissolution of CaCl2: CaCl2(s)→Ca2+(aq) +2Cl ̄(aq), △H = -81.5 kJ. An 11.0-g sample
• 7. Which one of the following statements is incorrect?(A) An unknown nonmetal element with a valence
• 8. For the transition of n = 3 →n = 2 to occur in the hydrogen atom, the wavelength of the resulting
• 9. Which one of the following statements is correct?(A) SO4 is more energetically stable than XeO4.(
• 10. Consider the following reaction: H2C=CH2(g) + F2(g)→H2FC-CFH2(g), △H = -549 kJ. Please estimate
• 11. Consider three molecules: A, B, and C. Molecule A has a hybridization of sp3. Molecule B has two
• 12. A certain metal fluoride crystalizes in such a way that the fluoride ions occupy simple cubic la
• 13. The solubility of CaCl2 in cold water is 74.5 g per 100.0 g water. Assuming i = 2.6 for CaCl2, t
• 14.For the reaction A →products, successive half-lives are observed to be 10.0, 20.0 and 40.0 min fo
• 15. Suppose the reaction system 2HI(g)⇌H2(g) + I2(g) has already reached equilibrium. Which of the f
• 16. In a 0.10-M aqueous solution of pyridine (Kь = 1.7 × 10-9), the percentage of pyridine (C5H5N) t
• 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 K
• 18. Which of the following mixtures would result in buffered solutions when 1.0 L of each of the two
• 19. Which of the following substances does not show increased solubility as the pH of the solution b
• 20. For the reaction at 800 K: N2(g) + 3F2(g)→2NF3(g), an equilibrium mixture contains the partial p
• 21. Which one of the following statements is correct?(A) The value of S° for N2O at 0 K is greater t