Chemistry 110 Name _______________________ Practice Exam 2B Section _______________________ Midterm 2 Signature _______________________ IMPORTANT: On the scantron (answer sheet), you MUST clearly fill your name, your student number, section number, and test form (white cover = test form A; yellow cover = test form B). Use a #2 pencil. There are 28 questions on this exam. Check that you have done all of the problems and filled in the first 28 bubbles on the scantron. The maximum score on this exam is 28 points. Your score will be reported in percents (max 100%). Exam policy • This cover sheet must be signed and handed in with your answer sheet for your exam to count. • Calculators with text-programmable memory are not allowed. • Relevant data and formulas, including the periodic table, are attached at the end of this exam. • Your grade will be based only on what is on the scantron form. • The answer key will be posted on the web after the exam (under "Exam Schedule"). Hints • As you read the question, underline or circle key words to highlight them for yourself. Avoid errors from "mis-reading" the question. • Pay attention to units and magnitudes (decimal places) of numbers obtained from calculations. • There is no penalty for guessing.CHEMISTRY 110 PRACTICE EXAM 2B --------------------------------------------------------------------------------- 1. How many valence electrons and lone pairs are in the structure of the ammonium ion? !#!valence!electrons!#!lone!pairs!A.!!8"0"B.!!10"1"C.!!8"1"D.!!10"2"E.!!12"3" --------------------------------------------------------------------------------- 2. Which of the following best represents the molecular structure of the molecule COS? A. I B. II C. III D. II and III are equally good representations. E. I and II are equally good representations. ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 3. What is the arrangement of electron domains about the central atom in formaldehyde, H2CO? A. Tetrahedral B. Trigonal planar C. Square planar D. Trigonal bipyramidal E. Linear --------------------------------------------------------------------------------- 4. Which of these molecules is/are non-polar? A. I only B. II only C. IV only D. I and IV E. II and III --------------------------------------------------------------------------------- ClClClClClClClClClIIIIII IV--------------------------------------------------------------------------------- 5. What functional groups are present in the molecule below? A. alcohol, amine, aldehyde B. amine, aldehyde, ketone C. amine, ketone, carboxylic acid D. alcohol, ketone, carboxylic acid E. ketone, carboxylic acid, ester --------------------------------------------------------------------------------- 6. What is the correct molecular formula for the following molecule? A. C4H8O2 B. C4H10O2 C. C5H8O2 D. C5H10O2 E. None of the answers listed here are correct --------------------------------------------------------------------------------- 7. Of the following, which element is the most electronegative? A. Ca B. At C. O D. Al E. Li ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 8. Which one of the following molecules is nonpolar? A. NH3 B. OF2 C. CH3Cl D. H2O E. BeCl2 --------------------------------------------------------------------------------- 9. What is the hybridization of As in the AsF4– ion? A. sp B. sp2 C. sp3 D. sp3d E. sp3d2 --------------------------------------------------------------------------------- 10. Hydrocarbons with 6 carbons in their longest chain have a parent name "hex" for "six". Which hydrocarbon has the same empirical formula as cyclohexane? A. benzene B. hexane C. benzane D. hexyne E. hexene ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 11. The structure of citric acid is given below. What is the hybridization of the two labeled carbons? ? "1!2!A.!!sp"sp2"B.!!sp2"sp3"C.!!sp3"sp2"D.!!sp3"sp"E.!!sp2"sp2"--------------------------------------------------------------------------------- 12. What is the percent carbon by mass in the compound below? A. 39.4% B. 42.2% C. 51.7% D. 56.3% E. 62.3 % ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 13. Select the electron-domain geometry and molecular geometry of chlorine in the perchlorate ion, ClO4−. !Electron!domain!geometry!molecular!geometry!A.!!trigonal"planar"tetrahedral"B.!!trigonal"planar"trigonal"planar"C.!!tetrahedral"tetrahedral"D.!!trigonal"pyramidal"trigonal"pyramidal"E.!!trigonal"pyramidal"trigonal"planar"--------------------------------------------------------------------------------- 14. Which of the following molecules are isomers? A. I and II only B. II and III only C. I and IV only D. I, II, and III E. All of them ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 15. Fill in the blanks: As bond order increases, the strength of a covalent bond _________ and bond length ______________. "strength!length!A.""increases"increases "B.""decreases"decreases"C.""increases"decreases"D.""decreases"increases "E.""increases "remains"constant"--------------------------------------------------------------------------------- 16. Which of the following have one or more atoms in the structure that have exceptions to the octet rule? BF3 NF3 SiF4 XeF4 A. BF3 and NF3 B. NF3 and SiF4 C. SiF4 and XeF4 D. BF3 and XeF4 E. NF3 and XeF4 --------------------------------------------------------------------------------- 17. Which bond in the molecule below is the most polar? A. C⎯H B. C⎯Cl C. C⎯Br D. C⎯O E. C⎯F --------------------------------------------------------------------------------- CCCCCCHClBrOHFH--------------------------------------------------------------------------------- 18. Which of the following