Chemistry 110 Name _______________________ PRACTICE EXAM 2C 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*2C*--------------------------------------------------------------------------------- 1. A neutral atom has the following electron configuration. What is the maximum number of covalent bonds this atom could form with hydrogen atoms? A. 1 B. 2 C. 3 D. 4 E. 5 --------------------------------------------------------------------------------- 2. How many valence electrons and lone pairs are in the structure of the N2H4 molecule? # valence electrons # lone pairs A. 10 1 B. 14 2 C. 14 1 D. 10 2 E. 12 3--------------------------------------------------------------------------------- 3. Which of the following is the most polar bond? A. O−F B. C−S C. N−F D. C−H E. B−F --------------------------------------------------------------------------------- 4. Which of following would have the highest dipole moment? A. HF B. HCl C. HBr D. HI E. All have the same dipole moment because they all contain H --------------------------------------------------------------------------------- 5. For which molecule is it not possible to draw a Lewis structure which follows the octet rule? A. HF B. CH2Cl2 C. N2O4 D. O3 E. PCl5 ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 6. Which of the following molecules has the longest C-C bond and the weakest C-C bond? C2F6 C2F4 C2F2 longest bond weakest bond A. C2F2 C2F2 B. C2F2 C2F6 C. C2F4 C2F4 D. C2F6 C2F6 E. C2F6 C2F2 --------------------------------------------------------------------------------- 7. Which of the following contains both ionic and covalent bonds? A. ClF B. SO2 C. NaCl D. SO3 E. NaCN --------------------------------------------------------------------------------- 8. Which of the following formulas may represent a cycloalkane with only one ring? A. C2H2 B. C6H6 C. C6H14 D. C6H12 E. C5H12 ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 9. What functional groups are present in the following aromatic molecule? i. ketone ii. amine iii. alcohol iv. aldehyde v. carboxylic acid A. ii, iii, and v B. i, ii, and iv C. ii, iii, and iv D. i, ii, and iii E. ii, iv, and v --------------------------------------------------------------------------------- 10. Which of the following is not an isomer of the others? --------------------------------------------------------------------------------- HONHOOH--------------------------------------------------------------------------------- 11. What are the hybridizations of carbons labeled 1 and 2 in a caffeine molecule (shown below)? Hybridization,of,*C1*C2*A.*sp2,sp2,B.*sp3,sp3,C.*sp2,sp,D.*sp3,sp2,E.*sp,sp2, --------------------------------------------------------------------------------- 12. Which of these molecules contains an odd number of electrons? i. NO ii. ClO2 iii. NO2 A. i only B. ii only C. iii only D. i and iii only E. All three contain an odd number of electrons. ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 13. Identify the molecules that have a zero net dipole moment: i. CS2 ii. CH2O iii. SeF2 A. i only B. i and ii only C. i and iii only D. ii and iii only E. i, ii, and iii --------------------------------------------------------------------------------- 14. Which of the following molecules has a trigonal bipyramid electron domain geometry? A. NF4+ B. SeF42+ C. PF4+ D. SF4 E. XeF4 ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 15. C, N, and O atoms readily form multiple bonds with each other. Which of these statements correctly explains why larger atoms in period 3 do not readily form multiple bonds with each other? i. The d-orbitals that become available in period 3 atoms such as Si, P and S get in the way and block the formation of multiple-bonds. ii. The energy required to promote electrons to p-orbitals in Si, P and S is so large than that the atomic orbitals cannot hybridize. iii. Unhybridized p-orbitals on Si, P, and S cannot form multiple-bonds because the atoms are too large for the p-orbitals to overlap. A. i only B. ii only C. iii only D. i and iii E. all three --------------------------------------------------------------------------------- 16. What are the electron-domain and the molecular geometries of SnCl3–? *electron;domain*geometry*molecular*geometry,A.*trigonal,pyramidal,tetrahedral,B.**trigonal,planar,trigonal,pyramidal,C.***tetrahedral,tetrahedral,D.*tetrahedral,trigonal,pyramidal,E.*trigonal,planar,trigonal,planar, ------------------------------------------------------------------------------------------------------------------------------------------------------------------ 17. Which of the