December 15, 2011Useful InformationGas Constant: R = 0.08206 L·atm/K·mol = 8.314 J/K·molCHEM 184 – Fall, 2011Final Exam (Red)December 15, 2011Instructions: Your scantron answer sheet must show your NAME and STUDENT ID NUMBER. (Begin all these entries atthe LEFT end of the space provided.)In answering the questions, be careful to fill in the corresponding circles according to the number of the question on the exam. USE A SOFT (No.2) PENCIL.Useful InformationGas Constant: R = 0.08206 L·atm/K·mol = 8.314 J/K·molConversion factors: 1 L·atm = 101.3 J1 atm = 760 torr = 1.013 x 105 PaPlanck’s Constant: h = 6.63 x 1034 JsAvogadro’s Number: Navo = 6.022 x 1023 molecules/molSpeed of light: c = 3.00 x 108 m/s Rydberg constant RH = 2.18 x 1018 J Debeye constant 1 D = 3.336  1030 C·m electron charge e = 1.6033  1019 CA periodic chart is given at the end of the exam1. The diameter of a neutral hydrogen atom is about 74 pm. Suppose that we could line up hydrogen atoms side by side in contact with one another. Approximately how many hydrogen atoms would it take to make the distance from end to end 1.0 mm?A. 1.4  104 atoms B. 1.4  107 atoms C. 1.4  108 atoms D. 1.4  109 atoms E. 1.4  1010 atoms2. If a car travelling at 80 miles per hour has a fuel efficiency of 11 miles per gallon, and a gallon of fuel costs $3.60, what is the cost of fuel consumed per minute? A. $0.12 B. $0.17 C. $0.24 D. $0.32 E. $0.4413. Express the answer to the following calculation to the correct number of significant figures. 128.16 + 2.10 × 101 = A. 128 B. 128.3 C. 128.37 D. 128.370 E. none of these4. A certain element, X, has two naturally occurring isotopes, X1 (69.15%) and X2 (30.85%), whose atomic masses are 62.92960 amu and 64.92779 amu, respectively. Calculate the average atomic mass of this element.A. 63.13 amu B. 63.38 amu C. 63.55 amu C. 63.89 amu E. 64.22 amu5. What is the average mass, in grams, of one atom of arsenic (As)? A. 5.48  10–23 g B. 33.0 g C. 74.9 g D. 1.24  10–22 g E. 8.04  1021 g 6. One nanogram doesn't seem like a very large number. How many helium atoms are there in1.00 ng of helium?A. 2.91  1012B. 1.08  1013C. 5.56  1013 D. 1.50  1014 E. 5.97  1014 7. Combustion of a 1.50 g sample of a hydrocarbon produces 5.07 g of CO2 and 1.04 g of H2O. What is the empirical formula of this compound?A. CH B. C2H3 C. CH2D. CH3E. CH4 8. An unknown compound has the empirical formula CH2. A 0.050-mol sample of this compound weighs 4.20 g. What is the molecular formula of this compound?A. C2H4 B. C3H6 C. C4H8 D. C5H10 E. C6H12 9. How many grams of Na2SO4 would be produced by the complete reaction of 20.8 g of NaOH , with an excess of H2SO4?H2SO4 + 2 NaOH  2H2O + Na2SO4A. 4.61 B. 9.23 C. 18.5 D. 36.9 E. none of these210. Given the thermochemical equationN2(g) + 3H2(g)  2NH3(g) + 92.6 kJcalculate the enthalpy change, H, for the reaction NH3(g)  1/2 N2(g) + 3/2 H2(g)A. –92.6 kJ B. –46.3 kJ C. 0 kJ D. 46.3 kJ E. 92.6 kJ11. The combustion of coal (i.e., carbon) produces heat according to the equationC(s) + O2(g)  CO2(g) Horxn = 393.5 kJ/molWhat mass of coal (in kg) must be consumed to produce 5.00 × 104 kJ of heat?A. 0.305 kg B. 1.53 kg C. 3.05 kg D. 15.3 kg E. 30.5 kg12. Consider the following two reactions:(1) A  B + C H1 = +100 kJ(2) B + D  E H2 = 200 kJDetermine the enthalpy change, H3, for the process(3) A + D C + EA. –300 kJ B. –100 kJ C. 0 kJ D. +100 kJ E. +300 kJ13. What is the energy of a mole of photons associated with light of frequency 1.25 x 1013 Hz?A. 8.29 x 10-21 J B. 3.69 x 10-20 J E. 1.80 kJ D. 4.99 kJ E. 22.2 kJ14. Calculate the wavelength (in nanometers) of the photon emitted by a hydrogen atom when its electron drops from the n = 4 state to the n = 2 state.A. 103 nm B. 486 nm C. 1280 nm D. 2630 nm E. 4650 nm15. Which of the following statements about the quantum numbers is false?A. The principal quantum number n has values from 1 to infinity.B. The angular momentum quantum number l has values from 0 to n-1.C. The magnetic quantum number ml has n values.D. The magnetic quantum number ml has values of – l to + l, including zero.E. The spin quantum number ms has values of +1/2 and –1/2.316. The following orbital diagram for the 2p subshell    .A. violates the Pauli exclusion principle.B. violates Hund’s rule.OC. violates both the Pauli exclusion principle and Hund’s rule.D. does not violate either the Pauli exclusion principle or Hund’s ruleE. violates Hess's Law17. Which element would you expect to have the largest effective nuclear charge, Zeff?A. K B. Ca C. Fe D. Br E. Kr18. Which element will display an unusually large jump in ionization energy values between I2 and I3, its second and third ionization energies?A. Na B. Mg C. Al D. Si E. P19. Which element would you expect to have the highest electron affinity?A. Mg B. Al C. Si D. P E. S20. Which of the following solids would have the largest lattice energy?A. Al2O3B. NaCl C. SrBr2D. CsI E. BaSO421. Which of the following covalent bonds is the most polar (i.e., highest percent ionic character)?A. N  N B. N  S C. N  O D. N  F E. N  I22. The diatomic molecule AB has a dipole moment of 1.21 D and the AB bond distance is 115 pm. Determine the percent ionic character of the bond in AB.A. 7.4% B. 15% C. 22% D. 27% E. 34%23. What is the formal charge on the doubly-bonded oxygen atom in NO2? (Hint: the structure is ON=O)A. 2 B. 1 C. 0 D. +1 E. +224. Which one of the following compounds does not follow the octet rule?A. NH3B. N2C. CO2D. NO2E. H2CO25. According to VSEPR theory, the geometry of the NO2 ion isA. bent B. linear C. square planar D. tetrahedral E. trigonal planar426. Which of the following molecules is (are) nonpolar? 1. OF2 2. H2S 3. XeF4 4. PCl5A. 1 only B. 2 only C. 1 & 2 D. 3 & 4 E. all of them27. According to valence bond theory, how might a  bond between the carbon atom and an oxygen atom in the CO2 molecule arise? (Consider the x-axis to be along the line joining the nuclei of the atoms.)A. The overlap of the 2py orbital on the C-atom with the 2py orbital on the O-atom.B. The overlap of an sp hybrid orbital on the C-atom