CHM 101 Mock Exam 3 Answer Key

CHM 101 Mock Exam #3 1. Which of the following statements regarding electromagnetic radiation (light) is not true? A. B. C. D. E. The wavelength of electromagnetic radiation is inversely proportional to its frequency. Each type of electromagnetic radiation has its own characteristic range of wavelengths and frequencies. The energy of electromagnetic radiation is directly proportional to its frequency. The distance between two corresponding points on a wave is its wavelength. The visible spectrum has the highest energy of any of the types of electromagnetic radiation. 2. For a light wave, calculate its wavelength in nanometers given that it has a frequency of 4.85 × 1014 s–1. E. 6.19 × 10–16 nm C. 1.62 × 106 nm D. 1.45 × 1023 nm A. 162 nm B. 619 nm 3. List the colors of visible light from lowest frequency to highest frequency. A. B. C. D. E. blue < violet < green < red < yellow red < yellow < green < blue < violet violet < yellow < green < blue < red violet < blue < green < yellow < red yellow < red < green < violet < blue 4. What is the energy of a photon of yellow light whose wavelength is 589 nm? Note that 1 nm = 10–9 m. C. 3.38 × 10–10 J D. 3.38 × 10–19 J A. 1.77 × 102 J B. 5.09 × 105 J E. 3.38 × 10–28 J 5. Which of the following statements is not true regarding the Bohr model of the hydrogen atom? A. B. C. D. E. In Bohr’s model, electrons could exist indefinitely in the space between orbits. Bohr’s model shows the electron circling the nucleus in fixed orbits. In Bohr’s model, when an electron emits energy, it can move to a lower-energy orbit. In Bohr’s model, when an electron absorbs energy, it can move to a higher-energy orbit. In Bohr’s model, n = 1 is the lowest energy orbit. Questions 6-7 are concerning your knowledge of atomic orbitals. 6. How many degenerate orbitals are in a p sublevel (subshell) such as a 2p, 3p, 4p, etc. sublevel? A. 1 B. 3 C. 5 D. 6 E. 7 7. Which of the images below represents a d orbital? A. B. C. D. E. None of the above Refer to the Periodic Table of the Elements for Questions 8-12. 8. Which of the given species has an orbital diagram matching what is shown below? ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ ↑↓ 1s 2s 2p 3s A. Ar B. Cl– ↑↓ ↑↓ ↑↓ 3p C. K+ D. Ca2+ -1- E. All of the above 9. Which of the following species has the electron configuration, [Kr] 5s 2 4d 10 5p 3? A. Kr B. Sr C. Sn D. Sb E. Te 10. Which of the following metals has the lowest ionization energy? A. Cs B. Rb C. K D. Na E. Li 11. How many valence electrons does an atom of oxygen, O, have? A. 2 B. 4 C. 6 D. 8 E. 10 D. N E. O 12. Which of the following elements is most electronegative? A. F B. Cl C. H Refer to the rules governing the drawing of Lewis structures and predicting molecular shapes for Questions 13-16. 13. In the Lewis structure for CH4, how many bonding electrons are present? A. 1 B. 2 C. 3 D. 4 E. 8 14. Which of the following has a Lewis structure that contains a double bond? A. H2 B. N2 C. O2 D. Cl2 E. H2O 15. Identify the main-group element that X in the following Lewis structure could stand for. O is oxygen. A. C B. N C. O D. Cl E. H 16. Which of the following statements about the structure and shape of ammonia, NH3, is not true? A. B. C. D. E. The parent structure of NH3 is tetrahedral (AX4). The molecule contains two non-bonding pairs of electrons. Each N—H bond in ammonia is polar. The atoms in the NH3 molecule are in a trigonal-pyramidal arrangement, making the molecule polar. The H—N—H bond angle is about 107°. 17. Which of the following represents a polar covalent bond? A. H—Cl B. Cl—Cl C. H—H D. F—F E. Br—Br 18. Which of the molecules shown below is/are polar? Assume in this question only that every covalent bond in a molecule is polar. A. I and II B. I, II, and III C. I, III, and IV D. II only -2- E. I and III Questions 19-22 are concerning your knowledge of ionic and covalent compounds. 19. Which of the following compounds is expected to have the lowest boiling point? A. KNO3 B. H2O C. MgCl2 D. CaF2 E. AlCl3 D. K+ E. P3− 20. Which ion is the largest ion among the following? A. S2− B. Ca2+ C. Cl− 21. Which of the image(s) below represents a compound that should be classified as covalent? A. II and V B. V only C. I and IV D. II and III E. II, III, and V 22. Which of the following substances has both ionic and covalent bonding? A. NaCl B. NaNO3 C. I2 D. AlCl3 E. NO2 Questions 23-25 are concerning your knowledge of gases. 23. Which of the following is/are likely to occur as a gas at room temperature? A. NH3 B. O2 C. CaF2 D. CH4 E. More than one 24. The two balloons shown in the figure each have the same volume, temperature, and pressure. Which of the following statements regarding the two balloons is correct? A. B. C. D. E. The mass of the O2 balloon is greater than the mass of the CO2 balloon. The CO2 balloon has fewer molecules than the O2 balloon. The O2 balloon has fewer molecules than the CO2 balloon. The two balloons contain the same number of gas molecules. The density of the O2 balloon is greater than the density of the CO2 balloon. 25. If the volume of a 3.4-L sample of gas at 1.4 atm is increased to 8.0 L at constant temperature, what is the final pressure? A. 11.2 atm B. 0.80 atm C. 8.4 atm -3- D. 0.60 atm E. 1.6 atm