Exam 3 - Review.ppt

DIRECTIONS For this practice review = hit the F5 key to go full-screen. One click of the spacebar will advance one problem ? the next click will fade-in the correct answer. That way looking through the questions in normal mode doesn?t spoil the answer for you! These questions are similar to those on the exam ? if you can complete the set quickly (on track to do ~20 in 50 minutes) you will probably be in good shape for the exam. If not = practice until you can finish them quickly! Please note that we did not cover material about the acid-base material of element oxides, and advanced rules for the transition metals! These will not appear on the exam. Work and Heat A system which undergoes an adiabatic change (i.e. = q = 0) and does work on the surroundings has w < 0 = ?E = 0 w > 0 = ?E > 0 w > 0 = ?E < 0 w < 0 = ?E > 0 w < 0 = ?E < 0 Energy Change A system receives 575 J of heat and delivers 425 J of work. Calculate the change in the internal energy = ?E = of the system. -150 J 150 J -l000 J 1000 J 575 J Standard Heats Calculate the ?H°rxn for the decomposition of calcium carbonate to calcium oxide and carbon dioxide. ?H°f [CaCO3(s)] = -1206.9 kJ/mol ?H°f [CaO(s)] = -635.1 kJ/mol ?H°f [CO2(g)] = -393.5 kJ/mol CaCO3(s) ? CaO(s) + CO2(g) -2235.5 kJ -1448.5 kJ -178.3 kJ 178.3 kJ 2235.5 kJ Heat Capacity If = as a pioneer = you wished to warm your room by taking an object heated on top of a pot-bellied stove to it = which of the following 15-pound objects = each heated to 100°C = would be the best choice? The specific heat capacity (in J/(g·K)) for each substance is given in parentheses. iron (0.450) copper (0.387) granite (0.79) gold (0.129) water (4.18) Thermo and Stoich. Galena is the ore from which elemental lead is extracted. In the first step of the extraction process = galena is heated in air to form lead(II) oxide. 2PbS(s) + 3O2(g) ? 2PbO(s) + 2SO2(g) ?H = -827.4 kJ What mass of galena is converted to lead oxide if 975 kJ of heat are liberated? 203 g 282 g 406 g 478 g 564 g Hess?s Law Use Hess's Law to calculate the enthalpy change for the reaction WO3(s) + 3H2(g) ? W(s) + 3H2O(g) from the following data: 2W(s) + 3O2(g) ? 2WO3(s) ?H = -1685.4 kJ 2H2(g) + O2(g) ? 2H2O(g) ?H = -477.84 kJ 125.9 kJ 252.9 kJ 364.9 kJ 1207.6 kJ None of these choices is correct. Behavior of Light Contact lenses can focus light due to the ___________ of the waves. diffraction reflection refraction dispersion interference Wavelength and Frequency A photon has an energy of 5.53×10-17 J. What is its frequency in s-1? 3.66×10-50 s-1 1.20×10-17 s-1 3.59×10-9 s-1 2.78×108 s-1 8.35×1016 s-1 Electromagnetic Spectrum Select the arrangement of electromagnetic radiation which starts with the lowest energy and increases to greatest energy. radio = visible = infrared = ultraviolet infrared = visible = ultraviolet = microwave visible = ultraviolet = infrared = gamma rays X-radiation = visible = infrared = microwave microwave = infrared = visible = ultraviolet deBroglie Wavelength A sprinter must average 24.0 mi/h to win a 100-m dash in 9.30 s. What is his wavelength at this speed if his mass is 84.5 kg? 7.29×10-37 m 3.26×10-37 m 5.08×10-30 m 1.34×10-30 m None of these choices is correct. Orbitals Atomic orbitals developed using quantum mechanics describe regions of space in which one is most likely to find an electron. describe exact paths for electron motion. give a description of the atomic structure which is essentially the same as the Bohr model. allow scientists to calculate an exact volume for the hydrogen atom. are in conflict with the Heisenberg Uncertainty Principle. Quantum Numbers The energy of an electron in the hydrogen atom is determined by the principal quantum number (n) only. the angular momentum quantum number (l) only. the principal and angular momentum quantum numbers (n & l). the principal and magnetic quantum numbers (n & ml). the principal = angular momentum and magnetic quantum numbers. Quantum Numbers Which of the following is a correct set of quantum numbers for an electron in a 5f orbital? n = 5 = l = 2 = ml = +3 n = 4 = l = 3 = ml = 0 n = 4 = l = 2 = ml = +1 n = 5 = l = 4 = ml = 3 n = 5 = l = 3 = ml = +1 Atomic Energies Energy states of atoms containing more than one electron arise from nucleus-electron and electron-electron interactions. Which of the following statements correctly describes these effects? Larger nuclear charge lowers energy = more electrons in an orbital lowers energy. Larger nuclear charge lowers energy = more electrons in an orbital increases energy. Smaller nuclear charge lowers energy = more electrons in an orbital lowers energy. Smaller nuclear charge lowers energy = more electrons in an orbital increases energy. None of these statements is generally correct. Quantum Numbers In a single atom = what is the maximum number of electrons which can have quantum number n = 4? 16 18 32 36 None of these choices is correct. Orbital Filling Select the correct set of quantum numbers (n = l = ml = ms) for the first electron removed in the formation of a cation for strontium = Sr. 5 = 1 = 0 = -½ 5 = 1 = 0 = ½ 5 = 0 = 1 = ½ 5 = 1 = 1 = ½ 5 = 0 = 0 = -½ Electron Configuration Notation Select the correct electron configuration for Te (Z = 52). [Kr]5s25p64d8 [Kr]5s25d105p4 [Kr]5s24d105p6 [Kr]5s24f14 [Kr]5s24d105p4 Isoelectronic Ions What is the correct order of decreasing size of the following ions? P3- > Cl- > K+ > Ca2+ Ca2+ > K+ > Cl- > P3- K+ > Cl- > Ca2+ > P3- K+ > Cl- > P3- > Ca2+ None of these is correct. Ionization Energy Identify the element of Period 2 which has the following successive ionization energies = in kJ/mol. IE1 = 1314 IE2 = 3389 IE3 = 5298 IE4 = 7471 IE5 = 10992 IE6 = 13329 IE7 = 71345 IE8 = 84087 Li B O Ne None of these choices is correct. Atom/Ion Sizes Which of the following elements has the smallest atomic size? Na Ar K Ca Kr