ap ch. 8-9 structures polarity review answers

Download AP Ch. 8-9 Structures Polarity Review Answers

Post on 22-Nov-2014




0 download

Embed Size (px)


Ch. 8-9: Bonding AP Review Questions **Read attached notes on isomers and coordination compounds.** 1) A chemist analyzed the carbon-carbon bond in C2H6 and found that it had a bond energy of 350 kJ/mol and a bond length of 1.5 angstroms. If the chemist performed the same analysis on the carbon-carbon bond in C2H2, how would the results compare? a) The bond energies and lengths for C2H2 would be the same as those of C2H6. b) The bond energy for C2H2 would be smaller and the bond length would be shorter. c) The bond energy for C2H2 would be greater and the bond length would be longer. d) The bond energy for C2H2 would be smaller and the bond length would be longer. e) The bond energy for C2H2 would be greater and the bond length would be shorter.

3) Which of the following does not follow the octet rule? a) PCl3 b) NO2 c) CO2 d) CO32- e) HCO31-

2) 2 HI(g) H2(g) + I2(g) For the reaction given above, Ho is 50 kJ. Based on the information given in the table below, what is the average bond energy of the H-I bond? Bond Average Bond Energy (kJ/mol) HH 440 II 150 a) 270 kJ/mol b) 540 kJ/mol c) 590 kJ/mol d) 640 kJ/mol e) 1180 kJ/mol

4) Which of the following violates the octet rule? a) NF3 b) IF3 c) PF3 d) SbF3 e) AsF3

**Exceptions to Octet Rule: See #4 above: it does not follow the octet rule (too many e-). It is stable, because it uses the empty "d" orbitals for hybrid orbitals. See #30: the NO does not follow the octet rule, since it has an unpaired electron. But it becomes stable by forming a dimer. Then all parts have 8 electrons!

5) Which of the following is expected to have the largest dipole moment? a) CH4 b) CO2 c) SF6 d) HCN e) Cl-

9) A linear molecule can have the general formulas AA, AB, or AB2. Given a molecule with the general formula AB2, which one of the following would be the most useful in determining whether the molecule was bent or linear? a) ionization energies b) electron affinities c) dipole moments d) electronegativities e) bond energies

6) The most polar of the following molecules is a) NH4+ b) SO42- c) CF4 d) CH3CH2OH e) CH3CH2CHO

7) The most polar covalent bond is found between which two elements based on the electronegativity of the elements? a) CN b) PF c) SO d) SiC e) OP

10) Of the following molecules, which has the largest dipole moment? a) CO b) CO2 c) O2 d) HF e) F2

8) Under identical conditions, which of the following gases is expected to deviate the most from ideal gas behavior? a) oxygen b) nitrogen c) methane d) carbon dioxide e) water

11) Which of the following contains nine sigma bonds and two pi bonds? a) CCl2F2 b) HCN c) HCHO d) CH3COOH e) CH2CHCHCH2

15) Which of the following contains exactly 18 valence electrons? a) CO32- b) CO2 c) NO2 d) SO2 e) SO3 12) Which of the following molecules has more than one pi bond? a) CO2 b) SO2 c) NH3 d) C3H6 e) CH2O

13) The Lewis-Dot structure of an oxygen molecule has a) one sigma bond b) one pi bond c) four nonbonded pairs d) (a), (b), and (c) e) (a) only

16) Which of the following has three resonance structures? a) H2SO4 b) NO2- c) SO3 d) HClO4 e) CO2

17) Which of the following has no resonance structures? a) CO32- b) CO2 c) NO2 d) SO2 e) SO3

14) Which of the following is used to describe the interaction of orbitals to form pi bonds?

18) The shape of CH4 is explained using a) VSEPR theory b) Hunds Rule c) transition state theory d) quantum numbers e) Heisenbergs uncertainty principle

23) How many of the following molecules have all of their atoms in the same plane? CH2CH2 F2O H2CO NH3 CO2 BeCl2 H2O2 a) 3 b) 4 c) 5 d) 6 e) 7

19) The bond angles about the carbon atom in the formaldehyde molecule, H2C=O, are approximately a) 180 degrees b) 120 degrees c) 90 degrees d) 60 degrees e) 109 degrees

20) Which of the following is predicted to have a square planar molecular structure? a) TeBr4 b) BrF3 c) IF5 d) XeF4 e) SCl2 24) Types of hybridization exhibited by the C atoms in propene, CH3CHCH2, include which of the following? I. sp II. sp2 III. sp3 a) I only b) III only c) I and II only d) II and III only e) I, II, and III 21) According to VSEPR, the repulsion between four regions of high electron density on a central atom are at a minimum when they a) point to the four corners of a square b) point to the four corners of a rectangle c) have a tetrahedral geometry d) are arranged at 90 degrees to each other e) have bi-pyramidal geometry

25) What is the percentage of s-character in sp3 hybrid orbitals? a) 25 b) 33 c) 50 d) 66 e) 75

22) The geometry of the nitrate ion, NO3-, is best described as a a) tetrahedron b) trigonal bipyramid c) linear structure d) triangular planar structure e) square pyramid

26) A molecule whose atoms are arranged linearly could have a central atom with which of the following hybridizations? I. sp II. sp3 III. dsp3 a) I only b) II only c) I and II only d) I and III only e) I, II, and III

Questions 30-34 a) SO2 b) SiH4 c) CO2 d) Be2 e) NO 30) In which of the choices is there polar double bonding in a nonpolar molecule? 31) In which molecule(s) does resonance occur? 32) In which molecule is the bond order 2 ? 33) Which of the molecules has four sp3 hybrid bonds? 34) Which molecule would you expect to be unstable on the basis of molecular orbital theory?

27) Which of the following does not form sp3 hybrid orbitals? a) carbon b) nitrogen c) hydrogen d) oxygen e) sulfur

28) Which of the following contains an atom with sp3 hybrid orbitals? a) CH4 b) HCN c) H2 d) BH3 e) CO2

29) Which of the following has d2sp3 hybridization with no unshared pairs on the central atom? a) H2O b) NH3 c) CH4 d) SF6 e) XeF4

35) An unknown substance is placed into a hot flame. The color of the flame is a bright red. Which of the following substances is most likely to be the unknown? a) Cu(NO3)2 b) NaCl c) KCl d) LiCl e) Ba(NO3)2

Questions 37-40 a) CO2 b) H2O c) SO2 d) NO2 e) O2 37) In this molecule, oxygen forms sp3 hybrid orbitals. 38) This molecule contains one unpaired electron. 39) This molecule contains no pi () bonds. 40) This molecule is the main product of photosynthesis.

36) The melting point of MgS is higher than that of KCl. Which of the following observations can explain this? I. Mg2+ has a greater positive charge than K+ II. S2- has a greater negative charge than ClIII. S2- has a smaller radius than Cla) III only b) II and III only c) I and III only d) I and II only e) I, II, and III

Questions 41-43 a) Heisenberg uncertainty principle b) Shrodinger equation c) Hunds Rule d) X-ray diffraction e) Photoelectric effect 41) Can be used to predict the paramagnetism of certain elements. 42) Predicts that it is impossible to simultaneously know both the location and momentum of an electron. 43) Predicts the locations and orientations of atomic orbitals.

44) Dimethylether (CH3 O CH3) and ethyl alcohol (CH3CH2OH) are examples of a) position isomerism b) structural isomerism c) stereo isomerism d) (a) and (b) e) optical isomerism

45) What is the proper name of [Co(NH3)5Br]Cl2? a) Cobaltpentaamine bromodichloride b) Pentaaminecobalt(III) bromodichloride c) Dichlorocobalt(V) bromodichloride d) Dichloropentaaminecobalt(III) bromide e) Pentaaminebromocobalt(III) chloride

46) Which formula correctly represents the diamminediaquadibromochromium(III) ion? a) [Cr(H2O)2(NH3)2Br2]+ b) [(NH3)2(H2O)Br2Cr]3+ c) [Cr(H2O)2(NH3)2Br2]3+ d) [(NH3)2(H2O)2Br2+Cr]+ e) [Cr(H2O)2(NH3)Br2]2+

48) Which of the following is not a complex ion? a) Cr2O72b) Ag(NH3)2+ c) FeCl63d) Cd(CN)422e) HgI4

47) Which of the following cannot be a complex ion? a) Fe(CN)63b) Cu(NH4)42+ 4c) Co(Cl)6 d) AlF63e) AgCl2

Written Questions: 1) Give the total number of valence electrons in species. Indicate the number of valence electrons on the central atom. Sketch and indicate the geometry of each of the following species. Give the approximate bond angles. Show unshared electron pairs only when they appear on the central atom. a) BeF2 b) NO21c) Br31d) XeF4

2) Oxygen is found in the atmosphere as a diatomic gas, O2, and as ozone, O3. a) Draw the Lewis structures for both molecules. b) Use the principles of bonding and molecular structure to account for the fact that ozone has a higher boiling point than diatomic oxygen. c) Use the principles of bonding and molecular structure to account for the fact that ozone is more soluble than diatomic oxygen in water. d) Explain why the two bonds in O3 are the same length and are longer than the bond length of the bond in diatomic oxygen.

3) Interpret each of the following four examples using modern bonding principles. a) C2H2 and C2H6 both contain two carbon atoms. However, the bond between the two carbons in C2H2 is significantly shorter than the bond between the two carbons in C2H6. b) The bond angle in the hydronium ion, H3O+, is less than 109.5o, the angle of a tetrahedron. c) The lengths of the bonds between the carbon and the oxygens in the carbonate ion, CO32-, are all equal and are longer than one might expect to find in the carbon monoxide molecule, CO. d) The CNO- ion is linear.

4) Consider the molecules PF3 and PF5. a) Draw the Lewis electron-dot structures for PF3 and PF5 and predict the molecular geometry of each. b) Is the PF3 molecule polar, or is it nonpolar? Explain. c) On the basis of bonding principles, predict whether each of the following compounds exists. In each case, explain your prediction. (i) NF5 (ii) AsF5

5) Explain each of the following observations in terms of the electronic structure and/or bonding of the compounds involved. a) At ordinary conditions, HF (normal boiling point = 20 oC) is a liquid, whereas HCl (normal boiling point = -114 oC) is a gas. b) Molecules of AsF3 are polar, whereas molecules of AsF5 a