It is most beneficial to you to write this mock midterm UNDER EXAM CONDITIONS. This means: Complete the midterm in 1.5 hour(s). Work on your own. Keep your notes and textbook closed. Attempt every question. After the time limit, go back over your work with a different color or on a separate piece of paper and try to do the questions you are unsure of. Record your ideas in the margins to remind yourself of what you were thinking when you take it up at PASS. The purpose of this mock exam is to give you practice answering questions in a timed setting and to help you to gauge which aspects of the course content you know well and which are in need of further development and review. Use this mock exam as a learning tool in preparing for the actual exam. Please note: Come to the PASS workshop with your mock exam complete. During the workshop you can work with other students to review your work. Often, there is not enough time to review the entire exam in the PASS workshop. Decide which questions you most want to review the Facilitator may ask students to vote on which questions they want to discuss in detail. Facilitators do not bring copies of the mock exam to the session. Please print out and complete the exam before you attend. Facilitators do not produce or distribute an answer key for mock exams. Facilitators help students to work together to compare and assess the answers they have. If you are not able to attend the PASS workshop, you can work alone or with others in the class. Good Luck writing the Mock Exam!! Dates and locations of mock exam take-up: Monday Nov. 12 5:30 7:30 pm (LA C264) Tuesday Nov. 13 6:00 8:00 pm (MC 5050)
Part A. Answer each of the six questions with a few sentences or equations where necessary. (5 marks each) 1. Why do liquid droplets often take the form of a sphere? 2. Which elements on the periodic table can have expanded octets? Explain why. 3. Why does carbon have a greater electron affinity than oxygen?
4. Compare the lattice energies of KBr and LiF 5. Why is b-carotene (shown below) a coloured compound? 6. Order the following elements in terms of increasing first ionization energy: P, S, Cd, In, and In +.
Part B. Answer any three of the following four questions (B1, B2, B3, B4). If you answer all four, the best three answers will count. (20 marks each) Note: for the purposes of this mock, answer all 4 questions. B1. Calculate the lattice energy of LiF(s) given the following information Enthalpy of sublimation for Li(s) = 161 kj/mol First ionization energy for lithium = 520 kj/mol F2(g) bond dissociation energy = 154 kj/mol EA for fluorine = -328 kj/mol Standard enthalpy of formation for solid LiF(s) = -617 kj/mol
B2. (a) Use the molecular orbital diagram for the NO molecule below to answer the following questions: (i) Calculate the bond order of NO (ii) Calculate the bond order of NO - (iii) Is NO or NO - more paramagnetic? (iv) Compare bond lengths of NO and NO -. (v) A diatomic molecule has a bond length of ½. How many bonds exist between the two molecules? (b) Order the following solids in terms of increasing melting point. K, Co, C (diamond), and I2 (s).
B3. CHEM 1001 AT (a) Which structure of CH3CO2H is more likely to exist? Show your process. 1 2 (b) Which molecule experiences greater surface tension? Circle either benzene (C6H6) or cyclohexanol (C6H11OH). Why? (c) Explain the differences in boiling points: a. Liquid nitrogen boils at 77K but liquid oxygen boils at 90K b. H2O boils at 273K but CO boils at 81.5 K
B4. (a) Fill in the table regarding the molecule of HCN shown in the image below. The dotted lines indicate an interaction between the corresponding orbitals. Bond Type Names of the Two Orbitals Involved in The Bond 1 2 3 4
(b) Use the VSEPR theory to predict the geometry, shape, and bond angles of SF4. What type of hybrid orbital is used by the inner atom? Draw the Lewis structure and indicate the direction of the net dipole if one exists. (c) Use the VSEPR theory to predict the geometry and shape of XeF2. What is the hybridization of the inner atom? Draw the Lewis structure and indicate the direction of the net dipole if one exists.
B4. (a) Calculate the radius of a body centered cubic structure of chromium (Cr). Chromium s density is 7.14 g/cm 3. (b) Gold packs in a cubic geometry. The edge length of its unit cell is 408 pm. Its density is 19.3 g/cm 3. In what unit cell arrangement are the gold atoms in?
Data and Constants R = 8.314 J K -1 mol -1 = 0.08314 L bar K -1 mol -1 NAv = 6.02 x 10 23 mol -1 1 amu = 1.66054 x 10-27 kg 1 atm = 760 Torr = 760 mm Hg = 1.01325 bar 1 bar = 10 5 Pa 1 Pa m 3 = 1 J 0 C = 273.15 K Density of water at 25 = 997 g L 1 R = 0.01097 nm -1 c = 3.00 x 10 8 m s -1 h = 6.63 x 10-34 J s electron mass = 9.11 x 10-31 kg