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<p>Chemistry 40S Supplementary Problems</p> <p>Electronic Structure, etc page 1</p> <p>Electronic Structure, Bonding &amp; The Periodic Table1. What are the definitions of wavelength and frequency of waves? 2. List the regions of the electromagnetic spectrum in order of increasing wavelength. 3. List the colours of the rainbow in order of increasing frequency. 4. What is the speed of light? What symbol is used to represent this quantity? 5. A recent news report stated that scientists had succeeded in slowing down the speed of light. How is this possible if the speed of light is supposed to be constant? 6. CJOB radio emits a signal at a frequency of 680 kHz. Calculate the wavelength of these radio waves. 7. A cordless telephone operates at 900 MHz. What is the wavelength of this signal? 8. Visible light falls between 400 nm and 700 nm. What is the range of frequencies for visible light? 9. A sodium lamp emits yellow light at a frequency of 5.1 x 1014 s-1. Calculate the wavelength of this light. 10. Which color of light is at the 400 nm end of the visible spectrum? 11. What is a quantum? What is a photon? 12. Calculate the minimum and maximum energies of light in the visible spectrum (see question 6). 13. How is the energy of electromagnetic radiation related to its wavelength? How is it related to the frequency of the radiation? 14. Calculate the energy and frequency of light where = 6.56 x 10-5 cm. 15. Microwave radiation may have = 3.2 x 1011 s-1. Calculate the energy and wavelength of this radiation. 16. Green light has an energy of 3.84 x 10-19 J/photon. Calculate and for this green light. 17. Calculate the energy of an electron in the 3rd energy level of a hydrogen atom. 18. Calculate the energy of an electron in the 2nd energy level of a lithium cation, Li2+. 19. An electron falls from n = 5 to n = 2 in a hydrogen atom. a) Is energy released or absorbed? Explain. b) Calculate the wavelength of light emitted during this electron transition.</p> <p>GPHS Science Department</p> <p>Chemistry 40S Supplementary Problems</p> <p>Electronic Structure, etc page 2</p> <p>20. An electron falls from n = 6 to n = 3 in a helium cation, He+. Calculate the wavelength of the light emitted during this transition. Would this light be visible to the naked eye? 21. Calculate the frequency of light that would allow an electron to jump from the 2nd to the 3rd energy level in a hydrogen atom. 22. What does it mean to say that an atom is in the ground state? What is the term applied when the atom is not in the ground state? 23. When an atom is ionized, it loses an electron. The electron can be thought to jump from to an energy level where n = . Calculate the maximum wavelength of radiation that would ionize a ground-state hydrogen atom. 24. What does the Heisenberg Uncertainty Principle state? 25. How did Bohrs model of the atom violate the Heisenberg Uncertainty Principle? 26. Is an electron a particle? or is it a wave? Explain. 27. What is an orbital? What is the probability of finding an electron in an orbital as it is pictured in your text? 28. What are the four quantum numbers that are used to describe an electron within an atom? What does each quantum number determine? 29. What does the Pauli Exclusion Principle state? 30. How many electrons can be held in any given orbital? This is a direct result of the Pauli Exclusion Principle. 31. How many electrons (in total) can be held on the 3rd energy level of an atom? Show how you calculated the answer. 32. Why is the electron configuration, 1s2 2s2 2p4 3s1, called an excited state? 33. Why is the electron configuration, 1s2 2s2 2p7 3s1, an impossible configuration? 34. Draw orbital diagrams for: a) silicon b) fluorine c) copper c) chromium b) chlorine</p> <p>35. Write electron configurations for: a) nitrogen</p> <p>b) argon</p> <p>36. Write abbreviated electron configurations for: a) calcium</p> <p>37. Identify the element whose valence electron configuration is 5s2 5p2. 38. Write the valence electron configurations for: a) bromine b) barium</p> <p>39. Identify the element whose electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2 3d2. 40. Identify the element whose abbreviated electron configuration is [Ar] 4s2 3d10 4p3.</p> <p>GPHS Science Department</p> <p>Chemistry 40S Supplementary Problems</p> <p>Electronic Structure, etc page 3</p> <p>41. Identify the element whose valence configuration is 5s2 5p5. 42. How many unpaired electrons are there in ground state atoms of a) carbon b) sulfur c) iron d) nickel 43. Which element(s) in period 4 have two unpaired electrons in their ground states? 44. Which two families of elements comprise the s-block on the periodic table? 45. Which family of elements comprises the d-block on the periodic table? 46. Which families of elements comprise the f-block on the periodic table? 47. Give the symbol of the atom whose ground state electron configuration is a) 1s2 2s2 2p3 b) 1s2 2s2 2p6 3s1 c) 1s2 2s2 2p6 3s2 3p6 4s2 d) [Xe] 6s2 4f14 5d10 6p2 48. Which family of elements has electron configurations ending in p5? 49. Describe the trend in atomic radii of elements within a period on the periodic table. Explain why the trend exists. 50. Describe the trend in atomic radii of elements within a group on the periodic table. Explain why the trend exists. 51. Lithium (Z = 3) has the following successive ionization energies: IE 1: 520 kJ/mol IE 2: 7 300 kJ/mol IE 3: 11 810 kJ/mol</p> <p>Explain why there is such a large increase between IE 1 and IE 2. 52. An element in period 3 has the following successive ionization energies: IE 1: 787 kJ/mol IE 2: 1577 IE 3: 3232 IE 4: 4356 IE 5: 21 270</p> <p>How many valence electrons does the element have? Identify the element. 53. What is the trend in first ionization energies within a period on the periodic table? Explain the trend. 54. Explain the following trend in first ionization energies: Li: 520 kJ/mol Na: 496 K: 419 Rb: 403 Cs: 376</p> <p>55. Arrange the following in order of increasing first I.E.: As, Sn, Br, Sr 56. Arrange the following in order of increasing atomic radius: Rb, As, Sb, Br, Sr</p> <p>GPHS Science Department</p> <p>Chemistry 40S Supplementary Problems</p> <p>Electronic Structure, etc page 4</p> <p>57. An element is considered to be paramagnetic if it has unpaired electrons. Which elements in the third period on the periodic table are paramagnetic? 58. Write the symbols of the four most electronegative elements, in order of increasing electronegativity. 59. What is a polar covalent bond? Discuss electronegativity and sharing of electrons in your answer. 60. Classify the following bonds as non-polar covalent, polar covalent, or ionic. Include calculations as part of your answers. a) Li-F b) C-Br c) Zn-Cl d) Cu-S 61. Classify the following bonds as non-polar covalent, polar covalent, or ionic. Include calculations as part of your answers. a) Na-O b) Al-I c) Si-O d) N-N 62. Arrange the following in expected order of increasing radius: K+, Cl-, S2-, Ca2+, Ar. Explain your answer. 63. Arrange the following in expected order of increasing radius: F-, O2-, Na+, Ne. 64. Draw the Lewis electron dot diagrams for: a) Mg 65. Draw the Lewis electron dot diagrams for: a) Na 66. Draw the Lewis electron dot diagrams for: a) Ca2+ 67. Draw the Lewis electron dot diagrams for: a) NH4+ 68. Draw the Lewis electron dot diagrams for: a) C2H6 69. Draw the Lewis electron dot diagrams for: a) N2 70. Draw the Lewis electron dot diagrams for: a) NaCl 71. Draw the Lewis electron dot diagrams for: a) NH3 b) O b) P b) O2b) H3O+ b) C2H4 b) O2 b) K2O b) CNc) Br c) Ar c) Fc) OHc) CO2 c) Br2 c) NH4Br c) NaBr</p> <p>72. What is a coordinate covalent bond? Draw the Lewis dot diagram for the hydronium ion and label a coordinate covalent bond. 73. Use the periodic table and concepts in this unit to answer the following: a) What is the electron dot formula for the element with Z = 51. b) Which of the following elements has the smallest radius? (Li, C, O, Br) c) What type of bonding would you expect between carbon and sulfur? d) Which element has the lowest first ionization energy Ca, Sr, or Mg? e) Which of the following elements is most metallic Si, S, N, or Cl? f) Which is larger P3- or P, Ca2+ or Ca?</p> <p>GPHS Science Department</p> <p>AP Chemistry 42S Supplementary Problems</p> <p>Chemical Kinetics page 5</p> <p>Chemical Kinetics Rates of Chemical Reactions1. Describe the collision theory of reactions. What is a successful collision? What factors determine if a collision is successful? 2. List the factors that affect the rates of chemical reactions. 3. Which of the following units would NOT be used to measure the rate of a reaction? Explain why. a) cm/s b) mL/min c) mol/L 4. Refrigerated food stays fresh for long periods. The same food stored at room temperature spoils quickly. Why? 5. Use collision theory to explain how temperature affects the rate of a reaction. 6. What is the activation energy of a reaction? How is this related to the rate of the reaction? 7. When the gas to a Bunsen burner is turned on, the gas does not begin to burn (react with the oxygen in the air) until a flame lights it. Once lit, however, it burns completely until the gas is turned off. Explain these observations. 8. A charcoal grill has air vents that can be adjusted. As the air vents are made smaller, explain what happens to the rate of burning of the charcoal. Will the temperature become higher or lower? 9. In your body, sugar is oxidized at 37C (body temperature). Outside the body, sugar will burn only at a temperature of over 600C. What accounts for this difference? 10. What is a catalyst? How does the catalyst affect the rate of a reaction? 11. What is an inhibitor? How does the inhibitor affect the rate of a reaction? 12. Explain the difference between a homogeneous and a heterogeneous catalyst. 13. What is the mechanism of a reaction? 14. What is an elementary step? What is the rate determining step of a mechanism? 15. Use collision theory to explain why most reactions probably occur through a multistep reaction mechanism. 16. Define the term reaction intermediate. Why are intermediates important for studying reaction mechanisms? 17. For each reaction below, explain how the rate of disappearance of each reactant is related to the rate of appearance of each product: a) H2O2 H2O + O2 b) CO + 2 H2 CH3OH</p> <p>GPHS Science Department</p> <p>AP Chemistry 42S Supplementary Problems</p> <p>Chemical Kinetics page 6</p> <p>18. What is an endothermic reaction? What is the sign of H for this reaction? 19. Construct and label a potential energy diagram from the information below. Calculate H for the reaction and include it on your diagram. P.E. of reactants = 300 kJ P.E. of products = 500 kJ Ea = 400 kJ</p> <p>20. Construct and label a potential energy diagram for the two-step reaction, using the information below. Calculate H for step 1 and H for the overall reaction. P.E. of reactants = 400 kJ P.E. of intermediates = 250 kJ Ea for step 1 = 200 kJ H for step 2 = -100 kJ Ea for step 2 = 300 kJ</p> <p>21. Which step in the reaction in the previous question is more likely the rate determining step? Explain your choice. 22. Use the P.E. diagram below to answer the questions that follow:800 kJ</p> <p>Energy Potential</p> <p>700 kJ 600 kJ 500 kJ 400 kJ 300 kJ 200 kJ 100 kJ</p> <p>Reaction Coordinatea) b) c) d) e) f) g) h) i) j) What is the P.E. of the reactants? What is the P.E. of the products? What is the P.E. of the intermediates? What is the activation energy of step 1? What is the activation energy of step 2? Which step is more likely the rate-determining step? Explain. What is H for the overall reaction? What is H for step 2? Is step 1 endothermic or exothermic? Explain. What is the P.E. of the second Transition State (activated complex)?</p> <p>GPHS Science Department</p> <p>AP Chemistry 42S Supplementary Problems</p> <p>Chemical Kinetics page 7</p> <p>23. Define the term activated complex. Why is it a complex? Why is it activated? Why is it sometimes called the Transition State? 24. What is a rate law? 25. The rate law for the reaction between bromine and nitrogen monoxide is given below: Br2 + 2 NO 2 NOBr rate = k [Br2] [NO] Indicate whether the following statements are true or false. Explain your reasoning. a) b) c) d) e) f) The reaction is 1st order with respect to bromine. The reaction is 2nd order with respect to nitrogen monoxide. The reaction is 2nd order overall. The reaction rate will double if the concentration of bromine is doubled. The reaction rate will double if the concentration of nitrogen monoxide is doubled. The reaction rate will double if the concentrations of both reactants are doubled at the same time. g) The reaction cannot involve a single-step reaction mechanism. (This is not an elementary reaction)</p> <p>26. Based on the rate law given in the previous question, propose two simple two-step reaction mechanisms for the reaction. Identify any intermediates in your mechanisms. Identify the rate-determining step in each mechanism. 27. The rate law for the decomposition of ozone into oxygen gas is given below: 2 O3 3 O2 rate = k [O3] Indicate whether the following statements are true or false. Explain your reasoning. a) The reaction is 2nd order with respect to the ozone. b) The reaction involves a single collision between two ozone molecules. c) If the concentration of ozone is tripled, the rate of decomposition will increase 9x. 28. Based on the rate law given in the previous question, propose a simple two-step reaction mechanism for the reaction. Identify any intermediates in your mechanism. Identify the rate-determining step in the mechanism. 29. A reaction has the experimental rate law, rate = k[A]2[B]. a) b) c) d) What is the overall order of the reaction? What would be the effect on the rate if [A] were tripled? What would be the effect on the rate if [B] were halved? What would be the effect on the rate if [A] were doubled while [B] was tripled?</p> <p>GPHS Science Department</p> <p>AP Chemistry 42S Supplementary Problems</p> <p>Chemical Kinetics page 8</p> <p>30. The hypochlorite ion, ClO-, undergoes a decomposition into the chlorate and chloride ions. A two-step reaction mechanism has been proposed for the decomposition: step 1: (slow) ClO- + ClO- ClO2- + Clstep 2: (fast) ClO2- + ClO- ClO3- + Cla) What is the net (overall) reaction for the decomposition reaction? b) What intermediate is formed in this reaction mechanism? c) Which step is the rate-determining step? Explain. 31. The reaction, 2 NO + 2 H2 N2 + 2 H2O, has been studied at 904C: Reactant Concentrations (mol/L) [NO] [H2] 0.420 0.210 0.210 0.105 a) b) c) d) e) 0.122 0.122 0.244 0.488 Rate of Appearance of N2 (mol/Ls) 0.136 0.0339 0.0678 ?</p> <p>Determine the rate law for the reaction. What is the overall order of the reaction? Calculate the value of the rate constant for the reaction at 904C. Calculate the rate of the reaction in trial 4 in the data table. Notice that the rates are measured for the appearance of N2. What would be the rate of appearance of H2O in trial 1? Explain.</p> <p>32. The reaction, 2 NO + O2 2 NO2, has been studied at 9...</p>

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