CHEMISTRY 110 EXAM 2 Oct.

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1 EMISTRY 110 EXAM 2 ct. 15, 2012 FRM A 1. Which of the following is an incorrect formula for a neutral compound made from the given ions?! "#$%&'! #'%&'! (&)*+,#! -.!! aluminum oxide Al 2 3 /.!! magnesium nitride Mg 3 N 2 0.!! calcium oxide a 1.!! ammonium chloride N 4 l 2.!! sodium phosphate Na(P 4 ) 2 2. ow many molecules are in 5.23 g of glucose ( )? A. 9.03! B. 3.05! ! D. 1.75! E. 4.20! Which of the following molecules are ionic? A. i only i. 2 ii. Kl iii. Na 2 3 B. ii only. i and iii D. ii and iii E. all three 4. Which of the following best describes propane, butane, and octane? A. The molecules contain only, and. B. The molecules contain only and and are isomers of each other.. The molecules contain only and and at least 1 double bond. D. The molecules contain only and and only single bonds. E. The molecules share no common characteristics.

2 Which of the following best describes the electron domain geometry of bromine pentafluoride? A. trigonal bipyramidal B. seesaw-shaped. tetrahedral D. square pyramidal E. octahedral 6. Which of the following will have less lattice energy than Nal? A. LiF B. Lil. NaF D. KBr E. MgS 7. What is the empirical formula for the compound drawn below? A. 3 4 B D. E Mass analysis of an unknown compound found it contained 5.532% hydrogen, % carbon and % nitrogen by weight. Mass spectrometry determined the molecular weight of the compound to be g/mol. What is the molecular formula of the compound? A. 6 5 N B. 5 3 N N 4 D N 3 E N 2 9. Which of the following is correct regarding structural isomers? i. They have different molecular formulas. ii. They have the same connectivity of the atoms. iii. They have the same molar mass. A. i only B. ii only. iii only D. i and iii E. all of these are true.

3 10. An unknown compound is analyzed and found to contain,, and Br. Upon further analysis, it is also found to be 45.9% carbon and 3.21% hydrogen. Which of the following could be the unknown compound? 12. Which one of the following molecules does NT have a geometric isomer? 11. Which of the followings pairs are isomers? A. II only B. II and III. I, II and IV D. I, II, III and IV E. II, III and IV I. II. III. IV. l l 13. Which functional group is NT present in the compound shown below. A. amide B. carboxylic acid. ester D. amine E. alcohol

4 14. Which of the following molecules will adopt a trigonal planar geometry? 16. Which figure best illustrates the hybridization of the central atom; sulfur in sulfur dioxide (S 2 ) and carbon in carbon disulfide (S 2 )? I. BF 3 II. lf 3 III. N 3 A. I only B. II only. III only D. I and II only E. I, II, and III 15. Which orbital hybridization(s) of the atoms is (are) contained in the molecule shown below? i. sp ii. sp 2 iii. sp 3 A. i and ii only B. ii and iii only. i and iii only D. iii only E. all three i. ii. iii. S2 S2 A. iii i B. ii ii. i iii D. ii i E. i i 17. Which of the following gives the correct number of! and " bonds in the molecule shown?! " A B D E. 25 6

5 18. What kind of intermolecular interactions are important in pure liquid acetic acid ( 3 )? 20. Use your knowledge of VSEPR theory to rank the indicated bond angles in order of decreasing angle. i. dipole-dipole ii. hydrogen bonding iii. dispersion force A. i and ii only B. iii only. ii only D. ii and iii only E. all three 19. Rank the following molecules in order of decreasing molecular polarity I. A. II = I > III B. I > II = III. II > III > I D. III > II > I E. I > III > II II. 2 III. 21. Which of the following molecules will experience dipole-dipole interactions? A. I > III > II B. I > II > III. II > III > I D. III > I > II E. II > I > III I. SF 4 II. 4 III. Sel 2 IV. PF 5 A. I only B. II and IV. I, III, IV D. I and III E. All of the above

6 22. A compound containing only P-l bonds was analyzed and found to contain by mass 22.6% phosphorus. What is the hybridization of the phosphorus atom? A. sp 3 d 2 B. sp 3 d. sp 3 D. sp 2 E. sp 23. Which of the following molecules has delocalized! bonds? A. I only B. II only. III only D. I and II E. I and III I. ozone ( 3 ) II. hydrogen cyanide (N) III. acetylene ( 2 2 ) 24. Why does the boiling point of straight-chain hydrocarbons increase with the length of the carbon chain? Boiling Point Boiling Points of Alkanes Number of arbons A. ydrogen bonding increases with chain length. B. Polarity decreases with chain length.. Intermolecular forces decrease with chain length. D. The number of isomers decreases with chain length. E. London dispersion forces increase with chain length.

7 25. alculate the % for the compound shown below 27. Which one of the following correctly depicts the -bonding between the two molecules? In these figures, hydrogen bonds are indicated with the hatched lines ( ). Br A. A. 0.48% B. 0.52%. 7.3% D. 46.3% E % 26. A student has 50 g of each of these molecules in a separate vial. Which sample has the greatest number of oxygen atoms? B.. D. E. Go on to the last page

8 28. Put these in order of increasing melting points. Ar LiF 6 14 A. Ar < 6 14 < LiF B. Ar < LiF < LiF < 6 14 < Ar D < Ar < LiF E. LiF < Ar < 6 14 END F EXAM FRM A 1. E 2. D 3. D 4. D 5. E 6. D 7. A 8. E A 11. B 12. D 13. E 14. A 15. B 16. D 17. E 18. E 19. B 20. E 21. D A 24. E E 27. B 28. A EMISTRY 110 EXAM 2 TBER 15, 2012 Answer Key