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Chemistry 106: General Chemistry Syracuse University Project Advance Exam #2, Fall 2001 Name Date The last page of the examination is a periodic table. (1) Which one of the following conditions would always result in an increase in E for a system? (a) (b) (c) (d) (e) (2) The system loses heat and does work on the surroundings The system gains heat and does work on the surroundings The system loses heat and has work done on it by the surroundings The system gains heat and has work done on it by the surroundings Cannot predict what happens because w and q are not state functions The value of H° for the following reaction is –126 kJ. 2 Na2O2(s) + 2 H2O(l) ------> 4 NaOH(s) + O2(g) Determine the amount of heat (in kJ) that would be evolved by the reaction of 25.0 g of Na2O2 with water. (a) (b) (c) (d) (e) (3) 20.2 40.4 67.5 80.8 126 What is the resulting temperature when 35 g of water at 75° C is mixed with 15g of water at 15° C? (Heat capacity of water is 4.184 J/g °C) (a) (b) (c) (d) (e) CHE 106 33° C 48° C 57° C 75° C 120° C 1 Fall 2001 Exam Questions (4) Given the following thermochemical equations: Fe2O3(s) + 3 CO(g) 3 Fe(s) + 4 CO2(g) H° = -28.0 kJ H° = +12.5 kJ 2 Fe(s) + 3 CO2(g) 4 CO(g) + Fe3O4(s) What is the value of H° for the reaction 3 Fe2O3(s) + CO(g) (a) (b) (c) (d) (e) (5) CO2(g) + 2 Fe3O4(s) kJ kJ kJ kJ -85 kJ Use the information in the table to calculate H° (in kJ) for the following reaction 4 NH3(g) + 5 O2(g) ------> 4 NO(g) + 6 H2O(l) Substance H2O(l) NO(g) NO2(g) HNO3 NH3(g) (a) (b) (c) (d) (e) (6) Hf° (in kJ/mol) -286 90 34 -207 -46 -1172 -150 -1540 -1892 none of the above Use the information in the table to calculate H° (in kJ) for the following reaction IF5(g) ------> IF3(g) + F2(g) H° = ? kJ IF(g) + F2(g) ------> IF3(g) IF(g) + 2 F2(g) ------> IF5(g) H° = -390 kJ H° = -745 kJ (a) (b) (c) (d) (e) CHE 106 +355 -1135 +1135 +35 -35 2 Fall 2001 Exam Questions (7) The heat capacity of copper metal is 0.38 J/g °C. Assume you had a 75 g cube of copper at 25° C. What would the final temperature of the copper be (in °C) if it absorbed 150 J of heat? (a) (b) (c) (d) (e) (8) Each of the following statements describes the significance of a certain key experiment or idea. Which one is not correct? (a) (b) (c) (d) (e) (9) 19.7 5.3 30.3 25.8 38.2 Planck’s successful explanation of the black-body radiation spectrum introduced the hypothesis that radiation is emitted not continuously but in discrete quanta. Rutherford’s experiment on the scattering of alpha particles showed that the mass of the nucleus is concentrated in a very small volume. The electron diffraction experiment demonstrated Heisenberg’s hypothesis that matter and energy are interconvertable. The solution to the Schrodinger wave equation for the hydrogen atom does not provide a detailed description of the electron’s position but only the probability of finding the electron in a given region of space. The phenomenon of radioactivity was discovered by Becquerel who observed that uranium salts emitted radiation that penetrated the black paper covering of photographic plates and darkened them as if they had been exposed to light. Which sketch represents an orbital that can have a azmuthal quantum number of 2? (1) (a) (b) (c) (d) (e) CHE 106 (2) (3) (4) (5) 1 2 and 4 4 and 5 2 and 3 2, 3, 4 and 5 3 Fall 2001 Exam Questions (10) Which of the following statements concerning the Bohr model of the hydrogen atom is not true? (a) (b) (c) (d) (e) (11) Which one of the following atoms has two unpaired electrons in the ground state? (a) (b) (c) (d) (e) (12) The theory successfully explained the observed emission and absorption spectra of the hydrogen atom. The theory requires that the greater the energy of the electron in the hydrogen atom, the greater its velocity. The theory requires that the energy of an electron in the hydrogen atom have only discrete values. The theory requires that the radii of the circular orbits of the electron have only discrete values. The theory requires that an electron move only between two discrete orbits. Na Ca P O Al Which orbital diagram represents a violation of Pauli principle? A B C D E (a) (b) (c) (d) (e) CHE 106 A B C D E 4 Fall 2001 Exam Questions (13) Which of the following combinations of quantum numbers do not represent permissible solutions of the Schrodinger wave equation for the hydrogen atom? A. B. C. (a) (b) (c) (d) (e) (14) ms 9 8 6 8 2 6 -4 -2 -1 -1/2 -1/2 -1/2 A B C B and C none of the above orbital orbit node wavefunction probability function [Ar]3d34s2 [Ne]5s1 [Ar]3d54s1 [Ar]3s13p6 [Xe]4f145d106s2 Which of the following transitions in the Bohr hydrogen atom model affords emission of the highest energy photon? (a) (b) (c) (d) (e) (17) ml Choose the electron configuration that corresponds to an excited state (a) (b) (c) (d) (e) (16) l The places where the value of 2 is zero are called a(n) (a) (b) (c) (d) (e) (15) n ni = 1 to nf = 6 ni = 6 to nf = 1 ni = 6 to nf = 3 ni = 3 to nf = 6 ni = 4 to nf = 1 The equation for the second ionization energy of chlorine is CHE 106 5 Fall 2001 Exam Questions (a) (b) (c) (d) (e) (18) Which of the following elements has the most exothermic electron affinity? (a) (b) (c) (d) (e) (19) S Cl Se Br B In which of the following series are the atoms arranged in order of decreasing first ionization energy? (a) (b) (c) (d) (e) (20) Cl2 + 2e- ------> 2ClCl(g) + e- ------> Cl-(g) Cl(g) -------------> Cl+(g) + e2Cl+(g) ------------> Cl2+(g) + eCl+1(g) ------------> Cl+2(g) + e- Sr > Ca > Mg Li > Be > B O > F > Ne Ne > Na > Mg Cl > Br > I Below is the Born-Haber cycle for the formation of sodium chloride. Which energy change corresponds to the heat of formation for NaCl? E n e r g y Na+1(g) + Cl-1(g) 2 4 Na(g) + Cl(g) 1 3 Na(s) + (a) (b) (c) (d) (e) CHE 106 1/ 2 5 6 Cl2(g) NaCl(s) 1 2 4 5 6 6 Fall 2001 Exam Questions