Homework 4 Student: ___________________________________________________________________________ 1. The formal charges on the nitrogen and oxygen in the following structures are, respectively A. +1, -1 B. 0, -1 C. +1, 0 D. 0, 0 2. Which of the following species has(have) a linear geometry? I. CO2 II. NO2+ III. NO2¯ A. only I B. only II C. I and II D. I, II, and III 3. The sp3 orbitals of carbon in CH4 are formed from the A. three 2p orbitals. B. 2s and one of the 2p orbitals. C. 2s and two of the 2p orbitals. D. 2s and the three 2p orbitals. 4. What is the Cl—C—Cl bond angle in CCl4? A. 60o B. 90o C. 109.5o D. 120o 5. Calculate the standard enthalpy change for the reaction 2C8H18(l) + 17O2(g) 16CO(g) + 18H2O(l). Given: 2C8H18(l) + 25O2(g) 16CO2(g) + 18H2O(l) H° = -11,020 kJ/mol 2CO(g) + O2(g) 2CO2(g) H° = -566.0 kJ/mol A. 10,450 kJ/mol B. 6,492 kJ/mol C. 15,550 kJ/mol D. -6,492 kJ/mol E. -10.450 kJ/mol 6. Given the thermochemical equation 2SO2 + O2 2SO3, H°rxn = -198 kJ/mol, what is the standard enthalpy change for the decomposition of one mole of SO3? A. 198 kJ/mol B. -99 kJ/mol C. 99 kJ/mol D. 396 kJ/mol E. -198 -198
7. Pentaborane B5H9(s) burns vigorously in O2 to give B2O3(s) and H2O(l). Calculate H°rxn for the combustion of 1 mol of B5H9. H°f[B2O3(s)] = -1,273.5 kJ/mol; H°f[B5H9(s)] = 73.2 kJ/mol; H°f[H2O(l)] = -285.8 kJ/mol. A. -1,2735 kJ/mol B. -4,543 kJ/mol C. -18,170 kJ/mol D. -9,086 kJ/mol E. -8,448 kJ/mol 8. The Lewis dot symbol for a lead atom is: A. B. C. D. E. 9. Which of these compounds is most likely to be ionic? A. KF B. CCl4 C. CS2 D. CO2 E. ICl 10. Which of these compounds is most likely to be covalent? A. KF B. CaCl2 C. SF4 D. Al2O3 E. CaSO4 11. Which of the following elements is the most electronegative? A. S B. Ru C. Si D. Te E. Cs 12. The total number of lone pairs in NCl3 is: A. 6 B. 8 C. 9 D. 10 E. 13 13. The Lewis structure for CS2 is: A. B. C. D.
14. Which of these Lewis structures is incorrect? A. B. C. D. E. 15. Which of these choices…