KEY Exam2 1311 F08 v A - keys to exam 2 version A, grading stytle included PDF

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keys to exam 2 version A, grading stytle included...

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Exam 2 F08 Key

Version A

1. The covalent bond with the greatest polarity would form for which of these atom pairs? A. C O B. B O C. Br Br D. C P E. S O ____________________________________________________________________________________________________________________________

2. What is the hybridization on the central atom in NO3 -? A. sp3d2 B. sp C. sp3d D. sp3 E. sp2 ____________________________________________________________________________________________________________________________

3. Which of the following does not typically exist as a homonuclear diatomic molecule? A. fluorine B. nitrogen C. oxygen D. phosphorus E. hydrogen ____________________________________________________________________________________________________________________________

4. The S – O bond order in the sulfate ion is: A. 1 B. 1.33 C. 1.5 D. 2 E. 1 and 2 ____________________________________________________________________________________________________________________________

5. Predict the ideal bond angles in AsCl3 : A. between 110 and 120° B. 180° C. 90° D. 109.5° E. 120° ____________________________________________________________________________________________________________________________

6. The chemical formula for manganese(III) nitrate is: A. Mg(NO2)3 B. Mn(NO2)2 C. Mn2(NO3)3 D. MnN3 E. Mn(NO3)3 ____________________________________________________________________________________________________________________________

7. Which of these ionic solids would have the largest magnitude lattice energy? A. NaF B. CaBr2 C. NaCl D. CaCl2 E. CaO ____________________________________________________________________________________________________________________________

8. Silicon, which makes up about 25% of Earth's crust by mass, is used widely in the modern electronics industry. It has three naturally occurring isotopes, 28Si, 29Si, and 30Si. Calculate the average atomic mass of silicon.

A. B. C. D. E.

28.73 amu 29.23 amu 27.98 amu 28.98 amu 28.09 amu

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9. Predict the molecular geometry (shape) and polarity of the SO2 molecule. A. None of these choices is correct. B. linear, polar C. bent, polar D. bent, nonpolar E. linear, nonpolar ____________________________________________________________________________________________________________________________

10. What is the hybridization of the central atom in CO3 -2 ? A. sp3d B. sp C. sp3d2 D. sp2 E. sp3 ____________________________________________________________________________________________________________________________

11. Which of the following is the empirical formula for hexane, C6H14? A. CH2.3 B. C0.43H C. C6H14 D. C12H28 E. C3H7 ____________________________________________________________________________________________________________________________

12. Which of these compounds is most likely to be covalent? A. CaO B. SrCl2 C. MgI2 D. Rb2S E. CS2 ____________________________________________________________________________________________________________________________

13. Which of the following atoms has exactly 5 valence electrons? A. S B. Na C. P D. Ne E. C ____________________________________________________________________________________________________________________________

14. What is the formal charge on phosphorus in the best Lewis structure for the phosphate ion? A. +2 B. 0 C. -1 D. -2 E. +1 ____________________________________________________________________________________________________________________________

15. What is the molecular geometry (shape) of the IBr3 molecule? A. seesaw (distorted tetrahedron) B. bent C. tetrahedral D. trigonal planar E. T-shaped ____________________________________________________________________________________________________________________________

16. The compound, P4S10, is used in the manufacture of safety matches. What is its name? A. phosphorus decasulfide B. phosphorus sulfide C. phosphorus sulfide D. phosphoric sulfide E. tetraphosphorus decasulfide ____________________________________________________________________________________________________________________________

17. Select the element whose Lewis symbol is correct.

A. b. B. e. C. c. D. a. E. d. ____________________________________________________________________________________________________________________________

18. What is the electron domain geometry of NO2 - as predicted by VSEPR theory? A. resonant B. linear C. trigonal planar D. tetrahedral E. bent ____________________________________________________________________________________________________________________________

19. What is the molecular shape of SiF6 2- as predicted by VSEPR theory?

A. B. C. D. E.

trigonal bipyramidal octahedral hexagonal tetrahedral see-saw

____________________________________________________________________________________________________________________________

20. What is the common name for HClO3? A. hydrogen trioxychloride B. hydrochloric acid C. chloroform D. chlorous acid E. chloric acid ____________________________________________________________________________________________________________________________

21. Carbon uses ______ hybrid orbitals in ClCN. A. sp2 B. sp3 C. sp D. sp3d E. sp3d2 ____________________________________________________________________________________________________________________________

22. Which one of the following compounds is polar? A. BrF5 B. XeF2 C. XeF4 D. CCl4 E. PBr5 ____________________________________________________________________________________________________________________________

23. The total number of lone pairs in NCl3 is: A. 13 B. 10 C. 9 D. 6 E. 8 ____________________________________________________________________________________________________________________________

24. The Lewis structure for CS2 is: A. B. C. D. ____________________________________________________________________________________________________________________________

25. The number of resonance structures for the best Lewis structure of the nitrate ion is: A. 2 B. 3 C. 4 D. None of these choices is correct. E. 1 ____________________________________________________________________________________________________________________________

26. The number of pi bonds in the molecule below is

A. 2 B. 6 C. 4 D. 10 E. 15 ____________________________________________________________________________________________________________________________

27. What is the formula for the ionic compound formed by calcium ions and nitrate ions? A. Ca3N2 B. Ca2NO2 C. Ca2NO3 D. Ca(NO3)2 E. CaNO3 ____________________________________________________________________________________________________________________________

28. Hydrazine, N2H4, is a good reducing agent that has been used as a component in rocket fuels. Select its best Lewis structure.

A. B. C. D. E.

b c d None of these choices is correct. a

____________________________________________________________________________________________________________________________

29. The formal charge on Cl in the structure shown for the perchlorate ion is

A. -2 B. +1 C. 0 D. +2 E. -1 ____________________________________________________________________________________________________________________________

30. Arrange aluminum, nitrogen, phosphorus and indium in order of increasing electronegativity. A. Al < In < N < P B. None of these choices is correct. C. In < P < Al < N D. In < Al < P < N E. Al < In < P < N ____________________________________________________________________________________________________________________________

31. Which one of the following Lewis structures is definitely incorrect?

A. d B. e C. a D. b E. c ____________________________________________________________________________________________________________________________

32. The F B A. 180° B. 90° and 180° C. 90° and 120° D. 120° E. 109.5°

F bond angles in BF3 are:

____________________________________________________________________________________________________________________________

33. Which of these compounds is most likely to be ionic? A. SF4 B. CO C. SO2 D. NCl3 E. BaCl2 ____________________________________________________________________________________________________________________________

34. What is the hybridization of As in the AsF4 - ion? A. sp2 B. sp3d2 C. sp3 D. sp3d E. sp ____________________________________________________________________________________________________________________________

35. Use VSEPR theory to decide which one of the following molecules/ions will have one or more 90° bond angles. A. CO2 B. NH3 C. PCl5 D. AlCl4 E. H2O ____________________________________________________________________________________________________________________________

36. The formula for sodium sulfide is: A. NaS B. NaS2 C. SeS D. Na2SO3 E. Na2S ____________________________________________________________________________________________________________________________

37. The ideal value for the bond angle indicated by "a" in the illustration below is:

A. B. C. D. E.

90° 109.5° 120° 150° 180°

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