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HOUR EXAM IIRK CHEM 103 NOVEMBER 25 2002 NAME: Key Page 1 of 13 EXAM IIRK NOVEMBER 25 2002 CH 103 DIRECTIONS • There is only one correct answer to each question unless otherwise noted. Any questions for which more than one response has been selected will not be counted • Your score is based solely on the number of questions you answer correctly. It is to your advantage to answer every question. • The best strategy is to arrive at your own answer to a question before looking at the choices. Otherwise, you may be misled by plausible, but incorrect, responses. YOUR SCORE FOR THE SECOND HOUR EXAM WILL BE THE AVERAGE OF YOUR SCORE ON EXAM II & EXAM IIR, OR YOUR SCORE ON EXAM II, WHICHEVER IS HIGHER. IF YOU SELECT “NONE OF THE ABOVE” as an answer, write your numerical answer, including units, next to it. IF YOU FIND YOURSELF BAULKED BECAUSE THERE IS A PIECE OF INFORMATION YOU DON’T HAVE, RAISE YOUR HAND. YOU MAY BE ABLE TO BUY THE INFORMATION FOR A POINT. TAKE A DEEP BREATH AND LET YOUR EYES FOCUS. RELAX YOUR SHOULDERS WHEN IN DOUBT CONVERT TO MOLES! Page 1 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK Key NAME: CHEM 103 NOVEMBER 25 2002 Page 2 of 13 INORGANIC NOMENCLATURE: 1. Name, by IUPAC rules, the following compounds: a. KBrO _______potassium hypobromite___ b. Al(IO2)3 c. AgClO3 ____aluminum iodite_____________ __________silver chlorate_____ d. Co(BrO4)3 ______cobalt(II) erbromate_______ e. P2O5 ______diphophorus pentoxide______ 5 pts: ____ 2. Give formulae for the following compounds: a. hydrogen peroxide: ______H2O2_______________________ b. carbon monoxide: _____CO_________________ c. Manganese (II) bromite : ___Mn(BrO2)2___________ d. Sulfurous acid: ____H2SO3____________ e. Nitric acid: ___HNO3_____________ 5 pts: ____ BONUS: What is the common name for dihydrogen dioxide? H2O2 hydrogen peroxide. Page 2 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK CHEM 103 NOVEMBER 25 2002 NAME: Key Page 3 of 13 3. Which statement is true? a) Carbon dioxide has POLAR bonds. b) Hydrogen fluoride is a NONPOLAR molecule c) Fluorine is the LEAST electronegative element. d) F2 is POLAR SHORT ANSWER: 4. a. Write the balanced equation for the reaction between nitric acid and potassium hydroxide: HNO3 + KOH H2O + KNO3 H+ + NO3- + K+ + OH- H2O + NO3- + K+ H+ + OH- H2O b. Write the balanced equation for the reaction between Acetic acid and potassium hydroxide. CH3COOH + KOH H2O + CH3COOK CH3COOH + K+ + OH- H2O + CH3COO- + K+ CH3COOH + OH- H2O + CH3COOc. Write the balanced NET IONIC equation for the reaction between potassium acetate and water H2O + CH3COOK CH3COOH + OHH2O + CH3COO- + K+ CH3COOH + OH- + K+ H2O + CH3COO- CH3COOH + OHd. Write the balanced equation for the reaction between lithium metal and water, producing lithium hydroxide (aq) and hydrogen gas. 2Li + 2H2O 2LiOH + H2 e. Write the balanced NET IONIC equation for the reaction between water and water H2O + H2O OH- + H3O+ BONUS: Write the net ionic equation for the reaction between magnesium oxide and water. MgO + H2O Mg(OH)2 Page 3 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK CHEM 103 NOVEMBER 25 2002 NAME: Key Page 4 of 13 4. In the sulfite ion, SO32-, the oxidation number for S is (A) - 6 (B) - 4 (C) 0 (D) + 4 (E) + 6 (F) None of the above S + 3(-2) = -2 5. In the chemical reaction, Mg (0) MgO (Mg2+ , O=) Mg oxidized 2Mg + O2 2MgO O2 (0) MgO (Mg2+ , O=) O reduced Which is true? a. b. c. d. e. Magnesium gets oxidized & O2 gets reduced. Magnesium gets reduced & O2 gets reduced. Magnesium gets reduced & O2 gets oxidized. Magnesium gets oxidized & O2 gets oxidized. Magnesium is a Lewis Acid. 6. Definition: OXIDIZED. In this reaction OXIDIZING AGENTS GET REDUCED. REDUCING AGENTS GET 2IO3- + 5Cu + 12H3O+ I2 + 5Cu2+ + 18H2O Identify the reducing agent: (A) (B) (C) (D) (E) IO3- IO3- (I = +5) I2 (0) reduced Cu (0) Cu2+ (+2) oxidized Cu H3O+ H2O None of the above. BONUS: What is the oxidation number of O in KMnO4 (potassium permanganate)? O is always –2 except in peroxides K (+1) + Mn + O (4 x –2) = 0 1 + Mn – 8 = 0 Page 4 of 13 Mn = +7 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: Key CHEM 103 NOVEMBER 25 2002 Page 5 of 13 7. Draw the Lewis structure of SO2 . Indicate its 3-D shape. (central atom underlined) 6+ 2(6) = 18 e.. :O: :O: .. O: .. S .. .. O: S 2 pts for Lewis structure, 2 pts for both LS’s, 1 pt for trigonal shape 8. Which one of these is a Lewis acid but NOT a Bronstead-Lowry acid?? (A) NH4+ (B) H3O+ (C) AlCl3 N H H H H O: H H (D) CH3COOH .. : Cl : H .. : Cl .. Al The Al atom has room to accept an addition pair of electrons but has no proton H+ to donate : O: C .. Cl : .. H3C .. ..O H 9. In the reaction: H2O + H2O OH- + H3O+ 1r 2r 1p 2p A. H2O molecule 1r is acting as a Bronstead base. B. H2O molecule 1r is acting as a Bronstead acid . DONATING H+ C. H2O molecule 2r is acting as a Bronstead acid. D. H2O molecule 1r is being oxidized. BONUS: In question 9 above, which species is the conjugate acid of water molecule 2r? 2p Page 5 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: Key CHEM 103 NOVEMBER 25 2002 Page 6 of 13 10. Which of the following is a weak acid? (A) Ba(OH)2 strong base (B) NH3 weak base (C) NH4+ weak acid (D) HNO3 strong acid (E) HI strong acid 11. The formal charge on the C in the Vitamin B1 carbanion is: THIS C : S Formal charge = 4 – 2 – ½(6) = : :C C N C R R R (A) +2 (B) +1 (C) 0 (D) -1 (E) -2 BONUS: What is the formal charge on the S in vitamine B1? FC = 6 – 4 –1/2(4) = 0 Page 6 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK CHEM 103 NOVEMBER 25 2002 NAME: Key Page 7 of 13 12. How many moles of HCl are needed to produce 10.00 Liters of carbon dioxide at STP? Assume that CaCO3 is in excess. CaCO3(s) + 2HCl(aq) CaCl2(aq) + H2O(l) + CO2(g) A B C HCl CaCO3 MW (g/mol) 36.45 100.1 CaCl2 111.0 CO2 44.01 H2O 18.01 D 0.4462 mol 0.2231 Mol 0.8923 Mol 10.00 Mol E None of the above 10.00 L CO2 STP STP. (1 mol/22.414 1 L/mol)STP = 0.4462 mol CO2 made @ 0.4462 mol CO2 (2 mol HCl/1 mol CO2) = BONUS: If you had 6.000 M HCl, how many L of HCL would you need to make the 10.00 L of CO2? 0.8923 mol HCl needed ( 1 L/6.000 mole HCl) = 0.1487 L of 6 M HCl (148.7 mL) Page 7 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK CHEM 103 NOVEMBER 25 2002 NAME: Key Page 8 of 13 13. Fuel cells burn Hydrogen gas, and produce virtually no pollution: 2H2(g) + O2(g) 2 H2O (l) Calculate the volume of H2 gas at 76000.0 Torr and 15.0 0C needed to produce 360.0 g of water. 360.0 g H2) (1 mol H2O / 18.0 g) = 20.0 mol H2O MW (g/mol) H3 2.01 O2 H2O 32.0 18.0 A B 0.00621 L 9.45 L C 0.260 L D E 4.72 L None of the above 20.0 mol H2O (2 mol H2/2 mol H2O) = 20.0 mol H2 PV = nRT => V = nRT/P T = 15.0 + 273.15K = 288.15 K P = 76000. torr (1 atm/760 torr) = 100.00 atm V = 20.0 mol (0.082057 L atm/K mol)(288.15 K)/100.00 atm 14. 25.7 L of Xenon gas is stored at 2660.0 torr. The pressure is changes to 7030.0 torr at constant temperature. What is the new volume? A B C D E 9.72 L 576 L 67.9 L 7390 L None of the above P ↑ V↓ 25.7 L (2660.0 torr/7030.0 torr) = BONUS: Calculate the mass of 1 molecule of sulfur dioxide (MW = 64.1 g/mol) 64.1 g/mol(1 mol/6.022 x 1023 molecules) = 1.06 x 10-22 g Page 8 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: CHEM 103 NOVEMBER 25 2002 15. Key Page 9 of 13 A correct statement of Boyle’s Law is: (If you can’t remember what Robert Boyle did, ask yourself, “Which one of these is true?”) (A) T = k/V (B) 1/T = kV (C) P = 1/T (D) VP = n (E) PV = k 16. You have a sealed container containing a mixture of nitrogen gas and hydrogen gas. The total pressure is 745.0 torr. The pressure of the N2 is 700.0 torr. The pressure of the H2 is: (A) 1445.0 torr PT = PN2 + PH2 (B) 45.0 torr 745.0 torr = 700.0 torr + PH2 (C) 0.980 atm (D) 1.060 atm (E) none of the above 17 . Calculate how many molecules of SO2 gas are present in a sealed, 22.4 L container at 760.0 torr and 273.15 K: A. 0.500 molecules B. 760.0 molecules PV = nRT n = PV/RT n = 760 torr(1 atm/760 torr)(22.4 L)/0.082057 L atm/K mol)(273.15 K) = 1 mol SO2 C. 1.00 molecules 1 mol SO2 (6.022 x 1023 molecules/mol) = D. 6.02 x 1023 molecules E. None of the above. Page 9 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: Key CHEM 103 NOVEMBER 25 2002 Page 10 of 13 18. NASA uses a balloon filled with He to monitor gamma rays in the upper atmosphere. The high altitude balloons can make it to an altitude of 4 km above the earth with a payload of 200-400 kg of instruments. Conditions at Sulphur Springs CO, where the balloon is launched: T = 28.0oC = 301.15 K P = 771.0 mm Hg V=? Conditions during the flight: T = -60.0 oC = 213.15 K P = 5.00 mm Hg V = 400,000.0 m3 Calculate the volume of the balloon on the ground at Sulphur Springs: (A) 3665 m3 T↑ V ↑ P↑ V↓ (B) 2.90 x 1010 m3 400000 m3 (301.15K/213.15K) (5.00 mm Hg/771.0 mm Hg) (C) 1836 m3 (D) -70400 m3 (E) None of the above 19. Elecromagnetic radiation detected bouncing back from Mt Ascutney has a wavelength of 3.34 x 106 μm. What is the frequency? A B C D E 89.5 0.0111 2.99 x 107 8.95 x 107 None of the above Hz Hz Hz Hz C = λν ν = c/λ λ = 3.34 x 106 μm (1 m/106 μm) = 3.34 m ν = 2.99 x 108 m/sec /3.34 m) = BONUS: True or false: The CO2 molecule is nonpolar. .. O .. C .. O .. Page 10 of 13 Each bond is polar, but the polarities cancel POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: CHEM 103 NOVEMBER 25 2002 Key Page 11 of 13 20. In another, parallel universe, the charge/mass ratio of a fundamental particle was measured and found to be + 5.685 x 10-12 coulombs/kg. From this one can conclude that: (A) The mass of the particle must be very large and/or the charge must be very small. (B) The particle has a net negative charge. (C) The mass of the particle must be very small and/or the charge must be very large. (D) This particle must be a positively charged electron (positron) 21. Calculate the kinetic energy in Joules of 2 molecules of H2 gas at 5.00 K . (MW = 2.00 g/mol). A. 2.07 x 10-22 J B. 125 J C. 6.25 x 10-23 J D. 500 J Ek = 3/2(nRT) for an ideal gas n = 2 molecules( 1 mole/6.022 x 1023 molecules) = 3.32 x 10-24 moles Ek = 3/2(3.32 x 10-24 moles)( 8.3145 J/mol K)(5.00 K) = KLAQUE’S BONUS: Define ELECTRONEGATIVITY. Electronegativity is a measure of the tendency of a combined atom to attract a shared pair of electrons to itself. Elements in the upper right-hand corner of the periodic table tend to be the most electronegative. Page 11 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: Key CHEM 103 NOVEMBER 25 2002 Page 12 of 13 SPECIAL UNITS & CONVERSION FACTORS Acceleration due to gravity (g) Avogadro’s number Bohr radius Boltzmann’s constant Electronic charge-to-mass ratio Elementary charge Faraday constant Gravitational constant (Universal) Mass of an electron Mass of a neutron Mass of a proton Molar volume of an ideal gas @ STP Permittivity of vacuum Planck’s constant Rydberg constant Speed of light in vacuo Universal gas constant g No ao kB -e/me e F G me Mn Mp Vm εo h R∞ c R 9.80665 m/sec2 6.0221367 x 1023 particles/mol 0.529177249 x 10-10 m 1.380658 x 10-23 J/K 1.75881962 x 1011 C/kg 1.60217733 x 10-19 C 9.6485309 x 104 C/mol 6.67259 x 10-11 m3/kg sec2 9.1093897 x 10-31 kg 1.6749286 x 10-27 kg 1.6726231 x 10-27 kg 22.41410 L/mol 8.854187817 x 10-12 C2/N m2 6.6260755 x 10-34 sec 2.1798741 x 10-18 J 2.99792458 x 108 m/sec Note the 2 sets of 8.314510 J/mol K units for R. Select 0.08205783 L atm/K mol the one with the units you need. Fgrav = -Gm1m2/r2 Felectrostatic = - [1/4πεo] q1 q2/r2 1 N = 1 kgm/sec2 1 J = 1 Nm = 1 kg m2/sec2 Arrhenius Equation: k = Ae-Eact/RT Formal charge = #valence e- - #nonbonding e- - ½ (#bonding e-) EK = 3/2(nRT) for an ideal gas 1 atm = 760 torr Page 12 of 13 POINTS THIS PAGE: _______ HOUR EXAM IIRK NAME: CHEM 103 NOVEMBER 25 2002 Key Page 13 of 13 PERIODIC TABLE OF THE ELEMENTS 1A 1 H 8A 2 He 3 Li 2A 4 Be 3A 5 B 4A 6 C 5A 7 N 6A 8 O 7A 9 F 6.941 9.012 10.81 12.01 14.01 16.00 19.00 20.18 11 Na 12 Mg 5B 6B 7B 15 P 16 S 17 Cl 18 Ar 24.31 4B 14 Si 22.99 3B 13 Al 19 K 20 Ca 21 Sc 22 Ti 23 V 24 Cr 25 Mn 26 Fe 27 Co 39.10 40.08 44.96 47.88 50.94 52.00 54.94 55.85 37 Rb 38 Sr 39 Y 40 Zr 41 Nb 42 Mo 43 Tc 85.47 87.62 88.91 91.22 92.91 95.94 55 Cs 56 Ba 57 La 72 Hf 73 Ta 74 W 132.9 137.3 138.9 178.5 181.0 87 Fr 88 Ra 89 Ac 104 Unq 105 Unp (223) 226.0 227.0 (261) 58 Ce 1.008 8B 4.003 10 Ne 1B 2B 26.98 28.09 30.97 32.07 35.45 39.95 28 Ni 29 Cu 30 Zn 31 Ga 32 Ge 33 As 34 Se 35 Br 36 Kr 58.93 58.69 63.55 65.39 69.72 72.61 74.92 78.96 79.90 83.80 44 Ru 45 Rh 46 Pd 47 Ag 48 Cd 49 In 50 Sn 51 Sb 52 Te 53 I 54 Xe (98) 101.1 102.9 106.4 107.9 112.4 114.8 118.7 121.8 127.6 126.9 131.3 75 Re 76 Os 77 Ir 78 Pt 79 Au 80 Hg 81 Tl 82 Pb 83 Bi 84 Po 85 At 86 Rn 183.8 186.2 190.2 192.2 195.1 197.0 200.6 204.4 207.2 209.0 (209) (210) (222) 106 Unh 107 Uns 108 Uno 109 Une (262) (263) (262) (265) (266) 59 Pr 60 Nd 61 Pm 62 Sm 63 Eu 64 Gd 65 Tb 66 Dy 67 Ho 68 Er 69 Tm 70 Yb 71 Lu 140.1 140.9 144.2 (145) 150.4 152.0 157.3 158.9 162.5 164.9 167.3 168.9 173.0 175.0 90 Th 91 Pa 92 U 93 Np 94 Pu 95 Am 96 Cm 97 Bk 98 Cf 99 Es 100 Fm 101 Md 102 No 103 Lr 232.0 231.0 238.0 237.0 (244) (243) (247) (247) (251) (252) (257) (258) (259) (260) END OF EXAM! Page 13 of 13 POINTS THIS PAGE: _______