CHEM 1211 Test III Multiple Choice (3 points each) 1. A chemical reaction in a bomb calorimeter evolves 5.17 kJ of heat. If the heat capacity of the calorimeter is 1.08 kJ/°C, what is the temperature change of the calorimeter? a. 0.209 °C b. 4.09 °C c. 4.79 °C d. 5.58 °C e. 6.25 °C 2. Which of the following chemical equations does not correspond to a standard molar enthalpy of formation? a. Ca(s) + C(s) + 3/2 O2(g) → CaCO3(s) b. C(s) + 1/2 O2(g) → CO(g) c. H2(g) + 1/2 O2(g) → H2O(λ) d. N2(g) + 2 O2(g) → N2O4(g) e. SO2(g) + 1/2 O2(g) → SO3(g) 3. Which of the following statements is INCORRECT? a. The location and the energy of an electron in an atom can be simultaneously known with little or no uncertainty. b. The energies of an atom's electrons are quantized. c. Quantum numbers define the energy states and the orbitals available to an electron. d. The behavior of an atom's electrons can be described by standing waves. e. Electrons have both wave and particle properties. 4. What type of orbital is designated n = 2, l = 0, ml = 0? a. 2s b. 2p c. 2d d. 2f e. none 5. Which of the following sets of quantum numbers refers to a 4p orbital? a. n = 1, l = 1, ml = -1 b. n = 1, l = 2, ml = -1 c. n = 4, l = 1, ml = 0 d. n = 4, l = 2, ml = -1 e. n = 4, l = 3, ml = +2 6. All of the following sets of quantum numbers are allowed EXCEPT a. n = 5, l = 3, ml = +2 b. n = 3, l = 2, ml = -1 c. n = 3, l = 0, ml = 0 d. n = 4, l = 4, ml = -2 e. n = 5, l = 3, ml = +37. Which of the following properties is associated with the value of the ml quantum number? a. the number of electrons in an orbital b. the size of an orbital c. the shape of an orbital d. the energy of an orbital e. the orientation in space of an orbital 8. Which of the following orbitals might have ml = -2? a. s b. s and p c. p and d d. d and f e. p, d, and f 9. Which of the following diagrams represent p-orbitals? a. (I) only b. (II) only c. (III) only d. (IV) only e. (I) and (II) 10. The Pauli exclusion principle states that a. no two electrons in an atom can have the same four quantum numbers. b. electrons can have either ± spins. c. electrons with opposing spins are attracted to each other. d. no two electrons in an atom can have the same spin. e. atoms with no unpaired electrons are diamagnetic. 11. What is the maximum number of electrons that can occupy the n = 2 shell? a. 4 b. 8 c. 18 d. 32 e. 50 12. Which element has the electron configuration 1s22s22p63s23p4? a. Mg b. S c. Si d. Se e. Ga13. Hund's rule states that the most stable arrangement of electrons (for a ground state electron configuration) a. has a filled valence shell of electrons. b. has two electrons per orbital, each with identical spins. c. has ml values greater than or equal to zero. d. has the maximum number of unpaired electrons, all with the same spin. e. has two electrons per orbital, each with opposing spins. 14. In general, atomic radii a. decrease down a group and remain constant across a period. b. decrease down a group and increase across a period. c. increase down a group and increase across a period. d. increase down a group and remain constant across a period. e. increase down a group and decrease across a period. 15. Which one of the following statements is INCORRECT? a. Ionization energy is always a positive value. b. Ionization energy is the energy required to remove an electron from a gaseous atom. c. For any element, the second ionization energy is larger than the first ionization energy. d. Ionization energy decreases across a periodic of the periodic table. e. Ionization energy decreases down a group of the periodic table 16. What is the expected number of valence electrons for an atom of a group 6A element? a. 0 b. 1 c. 2 d. 4 e. 6 17. Which of the following statements are CORRECT? 1. Ionic bonds form when one or more valence electrons are transferred from one atom to another.2. Covalent bonds involve sharing of electrons between atoms. 3. Ionic bond formation is always exothermic; covalent bond formation is always endothermic. a. 1 only b. 2 only c. 3 only d. 1 and 2 e. 1, 2, and 3 18. What is the total number of valence electrons in a carbon dioxide molecule? a. 4 b. 8 c. 16 d. 20 e. 2219. How many lone-pair electrons are on the carbon atom in CO2? a. 0 b. 1 c. 2 d. 3 e. 4 20. Which of the following is a correct Lewis structure for ozone, O3? a. 1 b. 2 c. 3 d. 4 e. 5 21. Which of the following are resonance structures for sulfur dioxide, SO2? a. 1 and 2 b. 2 and 4 c. 3 and 4 d. 1, 2, and 3 e. 2, 3, and 4 22. Use VSEPR theory to predict the electron-pair geometry and the molecular geometry of the nitrite ion, NO2-. a. The electron-pair geometry is linear, the molecular geometry is linear. b. The electron-pair geometry is trigonal-planar, the molecular geometry is bent. c. The electron-pair geometry is trigonal-planar, the molecular geometry is linear. d. The electron-pair geometry is tetrahedral, the molecular geometry is bent. e. The electron-pair geometry is tetrahedral, the molecular geometry is linear. 23. Use VSEPR theory to predict the molecular geometry of IF5. a. tetrahedral b. see-saw c. trigonal-bipyramidal d. square-pyramidal e. octahedral24. One resonance structure for thiocyanate ion is drawn below. What is the formal charge on each atom? a. S = 0, C = -1, N = 0 b. S = 0, C = 0, N = -1 c. S = -1, C = 0, N = 0 d. S = 0, C = +2, N = -3 e. S = -2, C = +4, N = -3 25. Which one of the following molecules is polar? a. CI4 b. PF5 c. NCl3 d. SO3 e. O2Problems SHOW WORK ON THE ANSWER SHEET (5 points) Give the ground state electron configuration of the following atoms: Arsenic (As) 1s22s22p63s23p64s23d104p3 Or [Ar] 4s23d104p3 Magnesium (Mg) 1s22s22p63s2 Or [Ne]3s2 (10 points) The enthalpy changes of the following reactions can be measured: C2H4(g) + 3 O2(g) Æ 2 CO2(g) + 2 H2O(l) ΔHo = -1411.1 kJ C2H5OH(l) + 3 O2(g) Æ 2 CO2(g) + 3 H2O(l) ΔHo = -1367.5 kJ Using these values, determine the enthalpy change for the reaction: C2H4(g) + H2O(l) Æ C2H5OH(l) C2H4(g) + 3 O2(g) Æ 2 CO2(g) + 2 H2O(l) -1411.1 …