I'IHI'ITIBIR UNIVERSITY OF SCIENCE nnd TECHFIOLOGY FACULTY OF HEALTH AND APPLIED SCIENCES DEPARTMENT OF NATURAL AND APPLIED SCIENCES QUALIFICATION: BACHELOR OF SCIENCE QUALIFICATION CODE: O7BOSC LEVEL: 7 COURSE CODE: ICH6OZS COURSE NAME: INORGANIC CHEMISTRY SESSION: NOVEMBER 2017 PAPER: THEORY DURATION: 3 HOURS MARKS: 100 FIRST OPPORTUNITY EXAMINATION QUESTION PAPER EXAMINER(S) DR. EUODIA HESS MODERATOR: P ROF HABAU KA KWAAM BWA INSTRUCTIONS Answer ALL the questions. PWI JE" Write clearly and neatly. Number the answers clearly All written work must be done in blue or black ink and sketches can be done in pencil 5. No books, notes and other additional aids are allowed THIS QUESTION PAPER CONSISTS 0F 9 PAGES (Including this front page, list of useful constants and Periodic Table)
SECTION A [40] QUESTION 1: Multiple Choice Questions [40] 0 There are 20 multiple choice questions in this section. Each question carries 2 marks. 0 Answer ALL questions by selecting the letter of the correct answer. 0 Choose the best possible answer for each question, even if you think there is another possible answer that is not given. 1. Which of the following conditions favours the existence of a substance in the solid state? A. High temperature B. Low temperature C. High thermal energy D. Weak cohesive forces 2. Which of the following is not a characteristic of a crystalline solid? A. Definite characteristic heat of fusion B. Isotropic nature C. A regular periodically repeated pattern of arrangement of constituent particles in the entire crystal D. A true crystal 3. Which of the following is an amorphous solid? A. Graphite B. Quartz Glass C. Chrome alum D. Silicon carbide 4. Iodine molecules are held in the crystal lattice by? A. London forces B. Dipole-dipole interactions C. Covalent bonds D. Coulombic forces Page 2 of 9
5. Which of the following is a network solid? A. 502 (solid) B. 12 C. Diamond D. H20 (ice) 6. What is the hybridisation of the carbon atoms in ethyne, CZHZ? A. Sp B. spz C. 3193 D. 31336! E. 5193612 7. What is the electronic geometry for 5 regions of high electron density on a central atom? A. octahedral B. square planar C. tetrahedral D. trigonal bipyramidal E. trigonal planar 8. What angle(s) are associated with a central atom that has tetrahedral electronic geometry? A. 109.5 B. 120 C. 120 and 180 D. 90 and 120 E. 90 and 180 9. Which one of the following molecules is polar? A. N2 B. R, c. C12 D. CO2 E. H20 Page 3 of 9
10. What kind of hybrid orbitals is utilised by the carbon atom in CR; molecules? A. Sp B. 5p2 C. 5103 D. sp3d E. sp3d2 11. The electronic geometry of the central atom in PC13 is A. pyramidal B. trigonal planar C. tetrahedral D. octahedral E. trigonal bipyramidal 12. The molecular geometry of PC13 is A. pyramidal B. trigonal planar C. tetrahedral D. octahedral E. trigonal bipyramidal 13. Choose the false statement from the following: A. A sigma bond is a bond resulting from head-on overlap of atomic orbitals. B. A pi bond is a bond resulting from side-on overlap of atomic orbitals. C. A double bond consists of one sigma bond and one pi bond D. A triple bond may consist of one sigma bond and two pi bonds or of two sigma bonds and one pi bond. E. A carbon atom involved in a double bond may not be sp3 hybridized. Page 4 of 9
14. How many lone pairs of electrons does the Lewis dot structure of H25 have around its central atom and what is the shape of the molecule? A. 0, linear B. 0, bent C. 1, trigonal planar D. 2, tetrahedral E. 2, bent 15. Number of dative bonds to central metal ion is its A. oxidation number B. compound number C. dative number D. coordination number 16. ions which are produced from ligands are A. Cation B. Anion C. Complex ion D. All of them 17. In a face centred cubic lattice the number of nearest neighbours for a given lattice point is A. 6 B. 4 C. 8 D. 12 18. Use VSEPR theory to predict the molecular geometry of 5032. A. bent B. tetrahedral C. square planar D. triangular planar E. triangular pyramidal Page 5 of 9
19. In a comparison with s-block elements, melting points of transition elements are A. Higher B. Lower C. Same D. Constant 20. Due to ligands' action of splitting colour of transition metal compound, this change occurs at A. s-orbital B. p-orbital C. d -orbital D. f-orbital SECTION B: [60] QUESTION 1: [39] 1.1 What is the coordination number of the metal in each of the following complexes? (10) a) [HgClalZ' b) [ZrF8]4' C) [Cl (H20)4Cl2]+ d) [Mo(CO)sBr] e) [Au(CN)2] 1.2 What is the oxidation state of the metal in each of the following complexes? (10) a) 180412" b) [Zng]4 C) [Cl (H20)4C 2]Jr d) [MO(CO)sBr]' e) [AU(CN)2]' 1.3 What are the geometries for complexes with coordination number 2, 4, and 6? Page 6 of 9
1.4 What is the name for each of the following coordination compounds? (10) a) K3[Cr(C204)2CI2] b) [Ag(NH3)2]N03 c) [Cu(en)2]504 d) Cs[FeCI4] e) (NH4)3[RhCI6] 1.5 For each of the following complex ions give the oxidation number of metal ion, depict low-spin or high-spin configurations, give the number of unpaired electrons in each state and tell whether or not its paramagnetic or diamagnetic. a) [RUIHZOI6I2+ bl [NiUVihld2+ QUESTION 2: 2.1 What are the shapes of the ions H30+ and CW}? ion. Draw the Lewis structure for each I11] (2) 2.2 Deduce whether nitrogen trifluoride, dichloromethane and sulfur tetrafluoride polar or non-polar. if polar, indicate the negative and positive sides of the molecule. (3) 2.3 Identify the hybridization of the central atom in following inorganic species: a) 3H4 b) SF; c) SOF4 (6) QUESTION 3: [10] Calculate the amount of energy (in kj) needed to heat 346 g of liquid water from 0 C to 182 C. Assume that the specific heat of water is 4.184 J/g- C over the entire liquid range and that the specific heat of steam is 1.99 J/g- C ( AHvap = 40.79 kj/mol for water). END OF EXAMINATION Page 7 of 9
' - USEFUL CONSTANTS: Gas constant, R = 8.3145 J mol l' K'1 = 0.083145 dm3' bar mol'l' K'1 = 0.08206 L atm mol'l' K 1 1Pa m3=1kpa.l =1N-m =1] 1 atm = 101 325 Pa = 760 mmhg = 760 torr Avogadro's Number, NA = 6.022 x 1023 mol'1 Planck s constant, h = 6.626 x 10 34 J5 Speed of light, c = 2.998 x 108 ms 1 Page 8 of 9
Page 9 of 9 PERIODIC TABLE OF THE ELEMENTS 1 18 1 2 H He 1.00794 2 3 14 5 1" '7 4.00260 3 4 5 6 7 8 9 10 Li Be B C N 0 F Ne 6.941 9.01218 10.81 12.011 14.0067 159994189984 20.179 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar 22.9898 24.305 3 4 5 6 7 8 9 10 11 12 26.9815 28.0855 30.9738 32.06 35.453 39.948 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co. Ni Cu Zn Ga Ge As Se Br Kr 39.0983 40.08 44.9559 47.88 50.9415 51.996 54.9380 55.847 58.9332 58.69 63.546 6538 69.72 72.59 74.9216 78.96 79.904 83.8 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.4678 87.62 88.9059 91.22 92.9064 95.94 (98) 101.07 102.906 106.42 107.868 112.41 114.82 118.69 121.75 127.6 126.9 131.29 55 56 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 Cs Ba Lu Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 132905 137.33 174.967 178.49 180.948 183.85 186207 1902 19222 195.08 196.967 200.59 204.383 2072 208.908 (209) (210) (222) 87 88 103 104 105 106 107 108 109 110 111 112 114 116 118 Fr Ra Lr Rf Db Sg Bh HS Mt Uun Uuu Uub Uuq Uuh Uuo (223) 226.025 (260) (261) (262) (263) (264) (265) (268) (269) (272) (269) Lanthlnidw: 57 58 59 60 61 62 63 64 65 66 67 68 69 70 La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb 138.906140.12140.90814424 (145) 150.36 151.96 15725158925 162.50161.930167.26166.934 173.04 Actinidefl 89 90 91 92 93 94 95 96 97 98 99 100 101 102 Ac Th Pa U Np PuAmCm Bk Cf Es Fde No 227.028 232.038 231.036 238.029 237.048 (244) (243) (247) (247) (251) (252) (257) (258) (259)