Exam 2 – Form D Key 1. A 2. E 3. A 4. C 5. B 6. B 7. C 8. C 9. B 10. C 11. D 12. C 13. B 14. E 15. C 16. D 17. D 18. B 19. A 20. A 21. A 22. A 23. SP = 1/2 [24 – 16] = 4 SP = 1/2 [32 – 26] = 3 a, b) S C SO Sb OO c) yes, no d) 2, 1 e) 2, 3 f) 2, 0 g) 180o, 109o h) linear, trigonal pyramidal i) sp, sp3For the next two questions, consider the following samples: A) 1.5 mol of C6H6 B) 1 mol of C4H10 C) 4 mol of H2O D) 2 mol of C2H6 E) 2 mol of CH4 1. Which sample contains the greatest number of total atoms? 2. Which sample contains the least number of total atoms? 3. Materials with low boiling points will also have: A) weak intermolecular forces and high vapor pressures B) weak intermolecular forces and low vapor pressures C) strong intermolecular forces and high vapor pressures D) strong intermolecular forces and low vapor pressures 4. Comparing CO2 gas and Cl2 gas both at room temperature, you would conclude: A) They have the same average kinetic energies and speeds B) They have the same average kinetic energy, but CO2 has the smaller speed C) They have the same average kinetic energy, but Cl2 has the smaller speed. D) They have the same speed but CO2 has the smaller average kinetic energy E) They have the same speed but Cl2 has the smaller average kinetic energy 5. Assuming other factors stayed constant, an increase in the temperature of a gas is consistent with: A) A decrease in the pressure of the gas B) An increase in the volume of the gas C) An increase in the number of moles of the gas D) All of these E) None of these 6. Select the correct statement: A) In a pi antibonding interaction, most of the electron density is between the nuclei, but above and below the internuclear axis. B) In a sigma antibonding interaction, there is very little electron density between the nuclei. C) In a pi bonding interaction, most of the electron density is between the nuclei, along the internuclear axis. D) In a sigma bonding interaction, there is very little electron density between the nuclei. 7. What can you say about the polarity of H2O, NH3 and SO2? A) H2O is polar, whereas NH3 and SO2 are not B) H2O and NH3 are polar, whereas SO2 is not C) H2O, NH3 and SO2 are all polar D) SO2 is polar, whereas H2O and NH3 are not E) SO2 and NH3 are polar, whereas H2O is notFor the next nine questions, consider this molecule. (Note: All atoms obey the octet rule. Lone pairs have not been shown, but must be considered when answering these questions.) CC CCCCHHH HCOOHC N CHHC C CClClNHHH1 23456789 8. What are the bond angles at carbon #3? A) 90o B) 109o C) 120o D) 180o 9. What is the hybridization at carbon #5? A) sp B) sp2 C) sp3 D) sp4 10. What is the shape at carbon #2? A) linear B) bent C) trigonal planar D) trigonal pyramidal E) tetrahedral 11. What are the bond angles at carbon #7? A) 90o B) 109o C) 120o D) 180o 12. What is the hybridization at carbon #8? A) sp B) sp2 C) sp3 D) sp4 13. What is the shape at nitrogen #6? A) linear B) bent C) trigonal planar D) trigonal pyramidal E) tetrahedral 14. How many pi bonds exist in this molecule? A) 3 B) 4 C) 5 D) 6 E) 7 15. What is the bond order of the bond between carbon #3 and carbon #4? A) 1 B) 1.33 C) 1.5 D) 2 E) 3 16. What is the bond order of the bond between carbon #5 and nitrogen #6? A) 1 B) 1.33 C) 1.5 D) 2 E) 3 For the next two questions, consider the following samples: A) 6 x 1023 HF molecules B) 2 mol H2O C) 3 mol BeH2 D) 3 x 1023 HCl molecules E) 0.5 mol of CO2 17. Which sample contains the least mass? 18. Which sample contains the greatest mass?19. In drawing Lewis structures, as we will do on the last page of this exam, we follow the octet rule. BUT, if you were asked to critique the following two structures of SO2Cl2 (neither of which follow the octet rule), which would you say is better, and why (lone pairs not shown)? S OOClClSClClOO#1) #2) A) Structure #1 is better because there are no formal charges on the O or Cl atoms B) Structure #1 is better because the O and Cl atoms have formal charges C) Structure #2 is better because there are no formal charges on the O or Cl atoms D) Structure #2 is better because the O and Cl atoms have formal charges 20. Consider the following three structures and select the accurate statement. (Note there is a negative formal charge shown on structure #3.) H C HOH CHHO HH CHHC OO123 A) Structure 1 has the shortest CO bond and structure 2 has the weakest CO bond. B) Structure 3 has the longest CO bond and structure 1 has the strongest CO bond. C) Structure 2 has the shortest CO bond and structure 3 has the weakest CO bond. D) Structure 1 has the longest CO bond and structure 2 has the strongest CO bond. E) Structure 2 has the longest CO bond and structure 3 has the strongest CO bond. 21. Select the material with the lowest boiling point A) H2 B) HF C) H2S D) N2 E) HCl 22. Which of the following represents a pi antibonding interaction? A B C D E23. Answer the following questions for CS2 and SbO33−, where all atoms obey the octet rule. a) (10 each) Draw the Lewis structure for each species (if resonance structures exist, only draw one). CS2 : SbO33− : b) (4 each) If you haven’t done so already, add formal charges to your structure. The remaining parts of this question will be graded on the structures you have drawn above. c) (2 each) Yes or no, do other resonance structures exist for: CS2 SbO33− d) (2 each) Based on your structure, what is the: CS bond order in CS2 SbO bond order in SbO33− e) (2 each) How many sigma bonds are in CS2 SbO33− f) (2 each) How many pi bonds are in CS2 SbO33− g) (4 each) What is/are the bond angle(s) in CS2 SbO33− h) (4 each) Based on your structure, what is the shape of CS2 SbO33− i) (4 each) Based on your structure, what is the hybridization at C in CS2 Sb in