Name: __________________________ Date: _____________ 1. Calculate the work, and determine whether it is done by the system or on the system when 45 J of heat is released and the internal energy increased by 313 J. A) B) C) D) E) +358 J, work done on the system +268 J, work done on the system +358 J, work done by the system +268 J, work done by the system −268 J, work done by the system 2. Consider this reaction ∆H = –92.6 kJ/mol N 2 (g) + 3 H 2 (g) 2 NH 3 (g) When 5.00 g of N 2 react with excess mol of H 2 to form NH 3 at 1 atm and a certain temperature, there is a decrease in volume equal to 49 L. Calculate ∆U for this reaction. (1 L.atm = 101.3 J). A) B) C) D) E) -11.6 kJ -97.6 kJ +97.6 kJ +43.6 kJ -14.6 kJ 3. A 22.0 g piece of metal is heated to 100.0°C and placed in 75.0 g H 2 O at 25°C. If the final temperature of the metal and water is 27.8°C, what is the specific heat of the metal in J/g·°C? A) B) C) D) E) 0.55 0.16 0.038 12 1.6 Page 1 4. Which one of the following reaction corresponds to the standard enthalpy of formation (ΔH f °) for CuSO 4 (s)? A) B) C) D) E) Cu(s) + S(s) + 2O 2 (g) CuSO 4 (s) Cu2+(aq) + SO 4 2-(aq) CuSO 4 (s) CuO(s) + SO 3 (g) CuSO 4 (s) CuS(s) + 2O 2 (g)CuSO 4 (s) Cu (s) + SO 2 (g) + O 2 (g)CuSO 4 (s) 5. A quantity of 3.00 x 102 mL of 0.950 M HCl is mixed with 3.00 x 102 mL of 0.220 M Ba(OH) 2 in a constant-pressure calorimeter. The initial temperature of both acid and base solutions is the same at 21.0° C. What is the final temperature of the mixed solutions? For the process: H+ (aq) + OH-(aq) → H 2 O(l) ΔH = -56.2 kJ/mol. Assume that the specific heat and density of solutions are the same as those of pure water. A) B) C) D) E) 24.0° C 18.2° C 52.3° C 25.6° C 36.8° C 6. What is maximum number of electrons that can have the following set of quantum numbers? n = 4 and m l = -1 A) B) C) D) E) 6 8 0 2 14 7. What is the energy of a one mole of photons of microwave radiation with a wavelength 0.122 m? A) B) C) D) E) 0.980 J/mol 1.63 x 10-24 J/mol 2.71 x 10-48 J/mol 1.62 x 10-19 J/mol 8.04 J/mol Page 2 8. How many electrons are there in all the p orbitals of a vanadium atom (V)? A) B) C) D) E) 12 6 3 5 10 9. Calculate the frequency of the light emitted by a hydrogen atom during a transition of its electron from the n = 4 to the n = 1 principal energy level. A) B) C) D) E) 3.08 × 1015 s-1 1.03 × 108 s-1 2.06 × 1014 s-1 1.35 × 10-51 s-1 8.22 × 1014 s-1 10. Calculate the wavelength for a neon atom (Ne) moving with a velocity of 2.00 x 105 m/s. A) B) C) D) E) 9.89 x 10-5 nm 1.89 x 10-7 nm 7.15 x 10-9 nm 9.75 x 1012 m 2.08 x 10-4 nm 11. Which of these ground-state ions has at least one unpaired electron? A) Sc2+ B) V5+ C) Mg2+ D) P3E) S2- Page 3 An element has an electron configuration of 1s22s22p63s2. Which electrons experience the greatest effective nuclear charge, and which experience the most shielding, respectively? 12. Greatest effective : most shielding nuclear charge A) B) C) D) E) 1s2 electrons 1s2 electrons 2s2 electrons 3s2 electrons 3s2 electrons : : : : : 3s2 electrons 2s2 electrons 3s2 electrons 2s2 electrons 2p6 electrons 13. The similar chemical properties of the elements in a given group in the periodic table is explained by the fact that atoms of these elements have: A) B) C) D) E) the same number of electrons in the valence shell. similar nuclear structures. the same number of protons. the same number of isotopes. the same number of electrons. 14. How many bonding electrons are there around the central Cl atom in a ClO 3 - anion in its "most preferable" Lewis structure? A) B) C) D) E) 10 8 12 6 5 15. The first ionization energy for S is lower than the first ionization energy for P because: A) B) C) D) E) S has a stronger electron-electron repulsion in the p orbital. Hund's rule is violated. P is more electronegative than S. P atom is bigger in size than S atom. S has more unpaired electrons than P. Page 4 16. Calculate the lattice energy of CaCl 2 using the following data. IE 1( Ca) = 590 kJ/mol, IE 2 (Ca) = 1145 kJ/mol, ∆H f [Ca(g)]=179.3 kJ/mol, ∆H f [Cl(g)] = 121.7 kJ/mol, ∆H f [CaCl 2 (s)] = −794.6 kJ/mol, EA(Cl) = 349 kJ/mol, A) B) C) D) E) 2254 1287 1254 1145 2154 17. Arrange calcium, rubidium, sulfur, and arsenic in order of decreasing electronegativity. A) B) C) D) E) S > As > Ca > Rb S > As > Rb > Ca As > S > Rb > Ca As > S > Ca > Rb Ca > S > As > Rb 18. Estimate the enthalpy of combustion reaction of methane (CH 4 )? (Note: You need to write and balance the reaction between CH 4 and O 2 ). Given: A) B) C) D) E) C-H 414 kJ/mol; C=O 799 kJ/mol; and O=O 498.7 kJ/mol; H-O 460. kJ/mol. -785 kJ/mol +785 kJ/mol -370 kJ/mol +370 kJ/mol +550 kJ/mol 19. Which one of the following follows the octet rule? A) B) C) D) E) CO 2 NO 2 ClO 2 BF 3 SF 6 Page 5 20. In the following Lewis structure for ClO 3 F, chlorine has a formal charge of ____ and an oxidation number of ____. A) B) C) D) E) 1, 7 7, -1 1, 1 1, -1 7, -7 Page 6 Answer Key 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. A A A A A A A A A A A A A A A A A A A A Page 7
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