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KFinals2 - Last Name 3 First Name A: Lab Sec. # ; T ;Lab...

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Unformatted text preview: Last Name 3 First Name A: Lab Sec. # ; T ;Lab day/time: QM ,ncuxo % g . Rolf Urgfiigfi‘ifizhj? l\/L \a ‘2 A =-2~51‘~*:CHEMI5TRV 2A \Sectionz \ f H / “we, Good luck © r \ I E AM 3 i‘ ’ Multi le hoice 1"" V (circle one) Instructions: gr“ 0 I {/63 CLOSED BOOK EXAM! No books, notes, or additional scrap paper are permitted. All information required is contained on the exam. Place all work in the space provided. If you require additional space, use the back of the exam. A scientific calculator may be used (if it is a programmable calculator, its memory must be cleared before the exam). (1) Read each question carefully. (2) For Parts I, there is no partial credit given and o_n|y answers marked on this cover page will be graded. (3) The last page contains a periodic table. You may remove them for easy access. (4) If you finish early, RECHECK YOUR ANSWERS! U.C. Davis is an Honor Institution 14.abcdei Possible Points # 1-16 (4 points each) # 17-19 (6 points each) Total Score (100) 15.a b c@e I._—__~_—___ 1®b c d e 1 0-1 6 total points: \éeuj gcct’mm 2— MTvH; Part I: Multiple Choice, Concepts (4 points each) Select the best answer and enter your choice on the cover sheet - No partial credit 1. Which oF the Following would be INCORRECT For molecules or atoms in which there are an odd number oF electrons total? a. They are called Free radicals. T b. In the lewis Formula they may have one less electron than octet on C,N,O,F.T @he best resong§ce Form is the one in which the formal change is lowest even iF it has to go over octe can C,N,O,F. "F d. The odd number oF electrons makes the molecule very unstable, because they need either one more or one less electron. T e. Resonance can have a stabilizing eFFect on Free radicals just as it does on ions. T 2. Which oF the Following is NOT TRUE For resonance structures. a. In resonance Forms only the electrons are moved never the atoms. 1- b. Some molecules with no net charge can have resonance Forms. T In some resonance Forms the octet rule is expanded. T den some extreme cases the sum oF all the Formal charges in the diFFerent resonance Forms «Wt. a.”ch ems-Q a flaw L/ c. Same fl 0“" e. Resonance is used to help explain relative stability oF moleculesgrrjons. .ex-wj 3. Which oF the Following would be INCORRECT For lewis Formulas: a. There are two diFFerent ways in which electrons are counted on each atom in lewis FormulasT ‘QC , <5 ¢~+~ b. The Formal charge assumes that the electrons in bonds are shared equally between the two atoms involved. '-ig-~ K \4 Web w pong ~44 :4 t- c. The net Formal charge must be equal to the charge on the compound/ionT @ IF you have counted up all the valence electrons First then put a complete octet on each atom counting Formal charge is no longer needed, because magically all the atoms will have a Formal charge oF zero. F M e. IF the order is not given to determine the best arrangement oF atoms in a molecule or ion each possible order must be checked by making a lewis structure with a complete octet on C,N,O, and F. \ 4. The lewis Formula For NHzCOOF has how many lone pairs oF electrons? t SZ/ l 0:: l :0; l t '1 u 5“ U1 M05 In the best se’r of resonance Forms For chlorile lhere are single bonds and i 5. double bonds respec’rively around fhe cen’rrol Cl. (1. 1, 3 C? b' 2'1 Q 8514.3 : C. 2, O ’ a “ 6 ‘ e. 3, 1 6. The number of in bonds in ’rhe C3H7N is: list-l " H a. O or 2 I l r ‘ 1.17%" b' 1 or 2 {flip-“CW C” N“ N w 4,1 (/fl M’H c. 2 or 3 _ l ( l 5., W” W911," 10.nin M M W low! /” e. Oorl N) f ‘ W+ (( aw? W, L figw“V3 «J .c O b c‘ I . 9.2 .5 gr‘ (:3 7. Which of fhe Followmg specues has boria’angles of aboul 109.5 ? AX“, #36:: A KAEL W‘K’ 1 f‘ a. HgTe (Te is no’r hybridized) 40° cfi‘fiéfiol ‘m {PX '-’ 5 Pa (“57’s BrOg‘ o '“ ~ (is M yr ‘7 a»? a; c m e six-av ;9l «mm m i: g) ‘ a '" 5E1” 1:“ 5 air—xx if 62? «w a, ~__,, 55- VLF 66" “ x. __3 §O‘”’"’” g «M x M 4”, g e p04 W I ‘5:ng ; 4‘91 i9! MC 8. Which of the following combinations of wave func’rions could give a szpif ihe sigma bxfikl onds are Found ’ro lie on the y-axis. Msw‘flw avg mflp (Mug i .C ‘Oq 0- ‘I’ x *0sz w, (r cypaSvlr-e ‘0 b- ‘1’2px'+11’2pX 934*“: if r, ll we. of? W”\$ . C'WPX'W X a"? 1*" m ° i 23W a?» 1 r i. 7’ \>y_ v v' 1..— 9. Which of the Following is ’rhe correc’r reacfion for ihe ’rhird ioniza’rion of Fe. :4 W 4,“; \ A? é“ :r—t’w 9/ b. Fe(g) -) Fe+3(g) + 3e- 59% PMLL. OW ©Fe+2(g) -) Fe+3(g) +fieb- O M, __.... g d. Fe+2(s) -) Fe+3(s) + 32— v ‘Q/ \ .F+3 -)F+2 3— ' xix/w,“ e e (g) e (9) + e Jr, \a Maw—w” 3 10. Given the two resonance Forms below which of the Following is faISe? 1.» _ 1.”. 1 H IOIE’S3 H IQIGW’?P I H I I IITJ—C—H M erl=C—-H H HY<\>1’ 2 9 WV / i a. The hybridization on C, N and O are all sp2 '1’ b. if the pi bonds are on the x—azgis then the atoms are all in the y 2 plane. T c. The First resonance Form ithnhe best. T” d. It can be argued that the terminal oxygen is not hybridized because quantum émdicts that it makes two bonds and it has two bonds.‘T" In the molecule there is one localized pi bond and 5yélocalized sigma bonds. T:— "" a —- 11. Which of the Followmg IS INCORRECT For the acnd HNO. H [wN 1 qr, : Mad“ I a. The H would be attached to the nitrogen. ‘T’ “ No 5AM b. The central atom in the molecule would best be described as an sp2 hybridizationy c. The central atom in the molecule would be nitrogen. ‘V he ion would have two resonance Forms after the acidic H comes off Tl; rig é. ‘ he oxygen Would have a sp2 hybridization. T” » gar” 12. For nitrate N03" which of the Following statements is INCORRECT? ’/ ‘ , 4/ a. The bond order of each N—O bonds is 1.33. 7’ Q ICU): b. The hybridization oF the all the atoms is spa. I/‘T/ c. The ions is non—polar. ' k I duThe ion one delocalized pi bond and three localized sigma bonds. r 19: 9 (we ion is trigonal {amid-m, 6/ A i - P" w‘MN-GNF w- ” (viral La 4:) ,3 . ‘ )9’3’” ©:$”9® \55/ \Q i Q 13. The electron configuration of CN+ ~— 0 0’ 3" 3 2 2 2 O 2\ I a. 0 230* 250 2p M76 ..._. b. 02250>i<225nzzp TT 2? W1]; .,,.C,.L..02250*22 n42p022p hd- 02250*225fl 2p) // V 529 /] [z e. (7 30' :JTF : fl ‘ LP \ / v 7'? an [103“ 4 u————— lacksfi” 14. Which of ’rhe molecules or ions would be mosl slable? 0. F2 1% b. F2‘ ‘5 C. F2+ l} d. Fz'z ‘ ‘0 15. Which of lhe Following species would be paramagnetic? a. C 2 8 «6 I """"'” w, w b. so 8 Z: "‘ ___, (,4- c. No+ l0 42-“ {if A.” 2a::3_o~ its, 1: e. 02-2 (4% 2 if 16. WhicW‘thriclizuli‘on"is ’rhe‘lowesl in energy? Lisa,“ 53‘ P V /c. «QMV‘S Us , ‘80 i!» “#15 “49 I .4! (a a —* W4 V kilos—3 Jr all. 3,144: w V“ 9*- o 5" 4.4mm 43c) L..;C3”O ,I‘ figme'K fl) [£53 4}” C4 A'Pt m '3 W4 xi“ 5 who a? ‘3 \«l 3 MW“ Part II: Fill-in the Blank/Workout Problems. Partial Credit May Be Given. Please show_all war/(for: calculations 17. (12 points) a. Draw out the complete MO energy diagram for NO'. Designating all the energy levels (i.e., 25, 2p, 0'2", 025* etc) b. Fill in the electrons using arrows For the atomic and the molecular orbitals. wcwi¢e m m“ k) (5,! ., HUT: c. Calculate the bond order. L d. is NO' paramagnetic or diamagnetic? ‘ M O ‘ 7w —é_ *- NNNNNN M..- Fara, 4+ Z. o4 i “W 7w? / tW/I ,~ 1 1;; 1’“! l‘f; ' A *’ *3 i 5” f r"! t a t» I flu, . {7%va a \ I“! v X's ' "5.3M ‘s 5, “it; ‘7 (Z or 7 l W ’1’ a“ K} C) v [:3 y ,_... ‘ g _ .. 4“ z a p a) t. ":5 . f/18. (10 pointS) ’ . w: e ' a. Arrange the Following in order of increasing polarity. + QM,” ’4 ( ' 0H2, 5H2, SH 743 [:41 < 5 l’z < 0H1 Kai; H l ‘Lag‘l" P aLLv— H 4:“? Arrange the following in order OFW’W. ; g6 R“ ................... mme LeaLlr Wé‘L PA’LV ’ . NHZF, NHZCl, NHgBr 412% NM. Br< NH l= ‘ x lag/Me k, ' - c. Arrange in order of Increasing ionic radius 3 7. '2, , ,7/ 3 MW,“ NG’, F", 8”, Ne, S"2 :5." < _ j, NL< (5 <5 < d. Arrange in order of increasing electron affinity “1175’ 4! “I " Vac—5 +¢ aim ¢.~ i I We, REIK,Ca,Gg;}>.s,Se, PCA. <Rb<l< <A5<_G'«e<5.e a {54 45' 451' $qu? epic e503? web‘ml» w-Lu «gurus. «Q.- e. An atom that has 1 sigma bond and 1 pi bond and 2 lone pairs of electrons around it has a hybridization oF 5 P1— and a electronic shape that is l i 5.4%»- . 19. (8 points) Use Lewis Formulas to show the best arrangement of atoms For a polyatomic ion withone C one 0 and one N and a net charge oF negative one. All (L g - possibilities (arrangementsi'oF‘atoms) must be shown For Full credit. 4 ‘ +“ “Z “we 1“ r -- _ 7 5‘9 435 &- qwcwcrow “N MC: o": we I N Em? "’ $11: 6 ‘ (4+ “WVWL‘ 4 , M " ll be HAG r r- (.5 Qt I” M , xx WWW + , i. i \WWMMV o‘F-e 2' » fllwags 0 I’m ¢mrfiy GP, _ .. ‘ .51- W Jam‘s; 4—“ foobar/“.5 c :30 .._.. M, V N T 49 RM H " *7... ' N 0 9 "MN \ (:1?W / m C/ No+—e. JAN-9" gawk“ fife acre e; 3..“ an, m “(TC-«MN 0" 15 ~Qmmme$ maker <3 41- r ._ V, _, . _- 5 "" “ya a (V . _ ; fl .0 1"" i {y ; Mire? Mir e: a 4“"'~é.;) we“ it 20. (10 points) Fill in the Following table (see the example at the top) For the determination of Formal charge(s) consider the Lewis Formula with the smallest Formal charges (lowest energy) Electron Ideal Polar or Hybridization Formal Oxidation molecule Group Molecular Bond Non-polar on underliagd, Charge(s) Number 0F Geometry Geometry Angles Molecule elem‘en On underlined the (central atom) element underlined element Trigonal— T-Shaped 90°, 180° polar sp3d Bipyramidal \uwaa M—Gw ‘pachv— Ewan 'y: ; rm +49 l ‘ x7. «2" . e ...
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This note was uploaded on 04/10/2010 for the course CHE 2a taught by Professor Tingguo during the Winter '08 term at UC Davis.

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KFinals2 - Last Name 3 First Name A: Lab Sec. # ; T ;Lab...

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