General Descriptive Chemistry 101 Exam 1 PDF

Name (Last, First): PID: Instructor: O Curtis O Pielak O Slowey O Werley Exam Classroom: ____________ General Descriptive Chemistry 101 Exam I DO NOT OPEN OR WRITE ANYTHING UNTIL INSTRUCTED TO DO SO Instructions: 1. Write your name and PID above. 2. Wri...

Name (Last, First): PID: Instructor: O Curtis O Pielak O Slowey O Werley Exam Classroom: ____________ General Descriptive Chemistry 101 Exam I DO NOT OPEN OR WRITE ANYTHING UNTIL INSTRUCTED TO DO SO Instructions: 1. Write your name and PID above. 2. Write your PID at the top of each page. 3. Read each question carefully. 4. Multiple-choice/many-select questions can be answered in pencil. 5. For many-select questions, mark “x” in boxes □ (please no stray marks). 6. All other questions must be written in pen. ANSWERS MUST BE PLACED IN BOXES or LINES (including CORRECT UNITS and sig figs). 7. SHOW YOUR WORK with correct units and sig figs. Partial credit based on work shown. 8. Use the periodic table. 9. Double-check your calculations. 10. Do not leave any answers blank. 11. Read and sign the honor pledge when, and only when, you finish taking the exam. 12. As part of the Honor Code, you may not discuss the contents of this exam with peers until it is returned to you. 13. Return all pages when you complete the exam. 14. Relax. You’ve got this. Honor Pledge: By signing below, I pledge that I have not violated the UNC Honor Code by receiving or giving unauthorized assistance on this exam. If I do not sign, then I acknowledge that I was not honorable in taking the exam and understand that it will simply not be graded, no questions asked. 101A _______________________________________________________________ (Signature) 101A  PID: ________________ 1 mL = 1 cm3 1 Å = 10-10 m c = 2.998 × 108 m/s h = 6.626 × 10-34 J·s c = λν E = hν 1 1 λ = h/(mu) ∆E = −hc𝑅𝐻 (𝑛2 − 𝑛2 ) where hcRH = 2.18 x 10-18 J 𝑓 𝑖 κ Q+ Q− 1.000 mol = 6.022 x 1023 Eel = 1.661 x 10-24 g = 1.000 amu d Density of water at 25oC = 1.00 g/mL 𝑟𝑎𝑡𝑒1 ℳ2 PV=nRT =√ Pi = Xi Ptotal 𝑟𝑎𝑡𝑒2 ℳ1 𝑛 R = 0.08206 L atm/mol K T(Kelvin) = T(oC) + 273.15 [𝑃 + 𝑎(𝑉)2 ] [𝑉 − 𝑛𝑏] = 𝑛𝑅𝑇  PID: ________________ Multiple-choice (5 pts each): Fill in the circle beside your final answer. No stray marks, please. 1. According to the Bohr Model, which of the following transitions corresponds to the absorption of a photon with the lowest frequency O A) n=1→n=5 O B) n=8→n=3 O C) n=4→n=6 O D) n=6→n=4 2. For which of the following could the Bohr Model be accurately applied to? O A) H- O B) H2 O C) Be3+ O D) Li+ 3. What is the result of the following calculation, reported with the correct number of significant figures? (107.2 𝑔 + 23.9 𝑔) = (27.986 𝑚𝐿) O A) 4.68449 g/mL O B) 4.7 g/mL O C) 4.68 g/mL O D) None of the above 4. Which phase change is depicted below? Does this phase change correspond to an absorption or release of energy? O A) Sublimation: Absorption O B) Deposition: Absorption O C) Sublimation: Release O D) Deposition: Release  PID: ________________ 5. Four students in lab performed mass measurements on a sample with a true value of 4.73 grams. Which student took the most precise collection of measurements? Chase 1.00 kg 1.01 kg 1.01 kg 0.99 kg Anna 4.21 g 4.73 g 4.90 g 5.21 g Bryn 1.20 mg 3.90 mg 4.73 mg 5.60 mg Gary 3.23 g 3.39 g 3.28 g 3.35 g O A) Chase O B) Anna O C) Bryn O D) Gary 6. Ejecting an electron on the surface of aluminum requires 4.08 electronvolts (eV) of energy. Which of the following light sources will eject an electron at the highest velocity? (1.0000 eV = 1.6022 x 10-19 J). O A) A bright source of 304 nm light O B) A dim source of 292 nm light O C) A bright source of 326 nm light O D) A dim source of 326 nm light 7. Using the table below, which of the following answers contains only extensive variables? I. Volume V. Temperature II. Mass VI. Density III. Color VII. Number of Molecules IV. Boiling Point VIII. Length O A) I, II, VII, VIII O B) III, IV, V, VI O C) I, III, VI, VIII O D) II, IV, V, VII O E) None of the above contain only extensive variables 8. Which answer(s) correspond to a chemical change in matter? (Select all that apply): Photosynthesis- the process of converting H2O and CO2 into O2 and sugar Melting solid silver until it is molten A wooden boardwalk becomes rough and splintery over time A copper-coated statue rusting  PID: ________________ THIS PAGE IS BLANK FOR YOUR THINKING  PID: ________________ Short Answer Part I: Provide your answers to of the following questions in the box provided. Be sure to show all work with units to be eligible to receive credit. 9. (7 pts) Using the information given, draw and label the mass spectrum for iridium, including percentages. Iridium is an element with two commonly occurring isotopes, one of which is Iridium-193 (percent abundance of 62.77%). Report the isotope masses on the plot to the nearest whole number. Percent Abundance (%) m/z (u) 10. (6 pts) Given that 1 formula unit of an XNO3 compound has a mass of 1.679x10-22 grams, what is element X? 11. (10 pts, 2 each) Fill in the blanks. A. Rank the atomic radii of the neutral atoms from least to greatest: Ca, Cl, P B. Rank the ionic radii of the ions from least to greatest: P3-, Ca2+, Cl- C. The Heisenberg Uncertainty Principle states that we cannot simultaneously know the exact and momentum of anything D. The abbreviated electron configuration for Tc3+ (Z = 43) is [Kr] E. Fill out the table below. Note the two blanks in “Symbol” that must be filled (0.5 points per blank) Nuclide Symbol Protons Neutrons Electrons ____ 2+ 117 78 ____  PID: ________________ Short Answer Part II: Provide your answers to of the following questions in the box provided. Be sure to show all work with units to be eligible to receive credit. 12. (9 pts) If you watched volleyball during the Summer Olympics this year, perhaps you were amazed by how fast the balls were flying through the air after being served (at a whopping 98.3 km/hr!!! which is about 61.1 mi/hr) Now that you’re a chemist, you know all things with mass have a De Broglie wavelength. kg ∙ m2 (Potentially useful info: 1 J is defined as 1 s2 ) What’s the de Broglie wavelength (in meters) of a regulation volleyball whose volume oz is 1.50x105 cm3 and density = 62.91m3 , immediately after being served at 98.3 km/hr? (Potentially useful info: 1.0000 kg = 35.274 oz) 13. (15 pts) Consider a perovskite, a mineral often used in solar cells, with the formula CaTiO3 (MW = 135.95 g/mol) for the following questions. A. (3 pts) How many oxygen atoms are in 12.05 picograms of this perovskite?  PID: ________________ B. (3 pts) Select all that apply: A perovskite could be classified as Molecule Homogeneous Mixture Compound Heterogeneous Mixture Atom Pure Substance CaTiO3 Perovskite Element Matter Structure C. (3 pts) In this perovskite, there are 3 O atoms. Using the diagram below, fill and label the energy-level diagram for a neutral oxygen atom. D. (3 pts) Draw the orbital corresponding to an electron in the highest subshell in the box provided. Include shading to represent phase if needed. E. (3 pts) Write a set of possible quantum numbers for an electron in the highest subshell n l ml ms  PID: ________________ 14. (13 pts) In this problem we will compare the radiation absorbed by a human in a 4- hour flight (the time needed to fly from Atlanta to California) to the radiation absorbed from a standard chest X-Ray. A. (8 pts) If the wavelength of light used in a chest X-Ray has a wavelength of 5.23 nm and there are 3.90x1013 photons absorbed by a human body during this process, what is the total energy absorbed, in joules (J)? B. (5 pts) In an average 4-hour flight, the human body absorbs 3.00 microsieverts per hour. How many 4-hour flights would it take a human of average mass (62 kg) to absorb the same energy as absorbed during a chest X-Ray? For this problem assume the energy of a total chest X-Ray is 1.24x10-3 J. (Note: this is NOT the answer from part A). Report your answer to the nearest whole number. (1 sievert = 1 J/kg)  PID: ________________ THIS PAGE IS BLANK FOR YOUR THINKING