AP Chemistry Practice Test Chapter 8 and 9 Multiple Choice Identify the choice that best completes the statement or answers the question. ____ 1. Which pair of atoms should form the most polar bond? a. F and B d. N and F b. C and O e. B and N c. F and O ____ 2. Which pair of ions should form the ionic lattice with the highest energy? a. Na and Br d. Li and O b. Li and F e. K and F c. Cs and F ____ 3. The electrostatic force of attraction is greatest in which compound? a. BaO d. MgS b. MgO e. CaO c. CaS ____ 4. Which molecule has the weakest bond? a. CO b. O c. NO ____ d. N e. Cl 5. For which species are octet resonance structures necessary and sufficient to describe the bonding satisfactorily? a. BCl d. BeF b. SO e. SO c. CO ____ 6. How are the bonding pairs arranged in the best Lewis structure for ozone? a. O–O–O d. OOO b. OO–O e. OOO c. OO–O ____ 7. Which species has the shortest bond length? a. CN b. O c. SO d. SO e. CO ____ 8. Which species requires the least amount of energy to remove an electron from the outermost energy level? a. Na d. O b. He e. Mg c. F ____ 9. Which species has a valid non-octet Lewis structure? a. GeCl d. SeCl b. SiF e. CO c. NH ____ 10. The Lewis structure for SeS has a total of a. 2 bonding pairs and 7 nonbonding pairs b. 2 bonding pairs and 6 nonbonding pairs c. 3 bonding pairs and 6 nonbonding pairs d. 4 bonding pairs and 5 nonbonding pairs e. 5 bonding pairs and 4 nonbonding pairs ____ 11. Given the following average bond enthalpies: C—C = 348 kJ/mol CC = 614 kJ/mol CC = 839 kJ/mol which of the following is most likely to contain a CC bond that has a bond enthalpy of 820 kJ/mol? a. C H d. C H b. C H e. C H c. C H ____ 12. Which of the following possess delocalized electrons? a. CH Cl d. (a) and (b) b. OCN e. (b) and (c) c. N O ____ 13. Which of the following is a property of a paramagnetic molecule? a. unpaired electron(s) and attraction to a d. all electrons paired and repulsion to a magnetic field magnetic field b. unpaired electron(s) and repulsion to a e. both paired and unpaired electrons and magnetic field repulsion to a magnetic field c. all electrons paired and attraction to a magnetic field ____ 14. Which molecule possesses a trigonal-bipyramidal structure? a. ICl d. PF b. BrF e. PF c. SF ____ 15. Which has a trigonal-pyramidal structure? a. BF b. NH c. SOCl d. (a) and (b) e. (b) and (c) ____ 16. In which molecule would you expect the central atom to use sp d hybrid orbitals? a. PF d. SiO b. BrF e. SO c. CO ____ 17. Which molecule does NOT have a dipole moment? a. CO d. XeF b. HBr e. NH c. CH Cl Other 18. Consider the following chemical species: the nitrogen molecule, the nitrite ion, and the nitrate ion. a. Write the chemical formulas for each of the species and identify the oxidation number of the nitrogen atom in each formula. b. Draw Lewis structures for each of the species. Where appropriate, draw resonance structures for each. c. List the chemical species in order of increasing NO bond length, the formula with the shortest bond first. Justify your answer. d. Write a balanced net ionic equation for the reaction of nitrogen dioxide with water. Comment on the molecular and/or ionic species that are formed. e. Draw each of the resonance structures for nitrogen monoxide and assign formal charges to each atom of each structure. 19. The molecules SF , SF , and SF are known. (a) Draw the Lewis structure for each. (b) Predict the electron-domain geometry and molecule geometry of each. (c) What type of hybrid atomic orbitals are used in each sulfur atom in bonding to the fluorine atoms? (d) Which are polar? (e) Why can sulfur exhibit a variety of sulfur-fluorine compounds but oxygen does not? AP Chemistry Practice Test Chapter 8 and 9 Answer Section MULTIPLE CHOICE 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: ANS: A D B E B B A D D C E E A D E B D PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: PTS: 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 OTHER 18. ANS: a. N , 0; NO , 3+; NO , 5+ b. :NN: Do I have to really draw them again? And again? And again? c. N 2 < NO 12 < NO 13 Multiple bonds are shorter and stronger than single bonds. The Lewis structure for N 2 shows that it has a triple bond. The resonance structures for nitrite show that each N–O bond has some double bond character. The resonance structures for nitrate show that each N–O bond has less double bond character than does nitrite. d. 2 NO2(g) + H2O(l) → H (aq) + NO (aq) + HNO2(aq) PTS: 1 19. ANS: (b) SF tetrahedral, bent (c) sp (d) polar (b) SF trigonal bipyramidal, “seesaw” (c) sp d (d) polar (b) SF octahedral, octahedral (c) sp d (d) nonpolar (e) Sulfur is a larger atom than oxygen and can accommodate more than four atoms about it. Furthermore, sulfur has accessible empty d orbitals which it can use to participate in more bond formation. PTS: 1