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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 N2(g) + 3 H2(g) 2 NH3(g) H = –92.6 kJ/mol When 5.00 g of N2 react with excess mol of H2 to form NH3 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 H2O 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 (ΔHf°) for CuSO4(s)? A) B) C) D) E) Cu(s) + S(s) + 2O2(g) CuSO4(s) Cu2+(aq) + SO42-(aq) CuSO4(s) CuO(s) + SO3(g) CuSO4(s) CuS(s) + 2O2(g) CuSO4(s) Cu (s) + SO2(g) + O2(g) CuSO4(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) → H2O(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 ml = -1 A) B) C) D) E) 6 8 0 2 14 7. What is the energy of an Avogadro’s number of photons of microwave radiation with a wavelength 0.122 m? A) B) C) D) E) 0.981 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 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 20Ne+ ion 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 : nuclear charge A) B) C) D) E) 1s2 electrons 1s2 electrons 2s2 electrons 3s2 electrons 3s2 electrons most shielding : : : : : 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 ClO3- 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 CaCl2 using the following data. IE1(Ca) = 590 kJ/mol, IE2 (Ca) = 1145 kJ/mol, H f [Ca(g)]=179.3 kJ/mol, H f [Cl(g)] = 121.7 kJ/mol, H f [CaCl2(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 (CH4)? (Note: You need to write and balance the reaction between CH4 and O2). 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 Page 5 19. Which one of the following follows the octet rule? A) B) C) D) E) CO2 NO2 ClO2 BF3 SF6 20. In the following Lewis structure for ClO3F, 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