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Chem 121 QU 912 Due in lecture Name_____________________________________________ page 1/2 DIRECTIONS: Write the correct answers in the appropriate blanks. Round – off problem answers (but not numbers within a problem) to 3 significant figures. Write units. Text: CHEMISTRY A molecular approach (2nd Ed.) by Tro. 1. Answer the following from text pages 393-397. →Draw Lewis Structures in the rectangles for the following: 38a↓ 52c↓ Note any ion charges (ions) such as Mg2+. 60d↓ 64c↓ 2. Answer the following from text pages 447-453. →Draw the molecular geometry for: 40b↓ 40b↓ 42b↓ 42b↓ __________________ Electron geometry↑ __________________ Molecular geometry↑ _________________ Bond angle↑ →52c SeF6 is ( polar __________________ Electron geometry↑ __________________ Molecular geometry↑ _________________ Bond angle↑ Nonpolar ) ←Circle the correct answer. 3. Rank order the following elements (S, F, Rb, O, Sr, Ge) from highest to lowest electronegativity. →Highest ________ ________ ________ ________ ________ ________Lowest 4. Arrange the compounds ( CH4, NaF, SO2, CF4, NaBr, CH3OH ) in order of increasing boiling temperature. →Lowest ________ ________ ________ ________ ________ ________ Highest 5. Explain how the Tyndall effect distinguishes a colloid from a solution in the space below: Chem 121 QU 912 Due in lecture Name_____________________________________________ page 2/2 6. Answer the next 6 questions concerning FCN. →______ Write the number of valence electrons. → None the possibilities shown have the correct number of electrons. Add extra electrons where appropriate. :F:C:::N: :F:N:::C: :N::C:::F: :N:F:::C: Cross out the electron dot formula that cannot possibly be correct. Write formal charges above F, N, and C in the formulas not crossed out. FC = valence electrons - 1/2 bonding electrons - lone pair electrons Circle the electron dot formula most likely to be correct π ←Write the most likely correct (circled) line bond formula in the rectangle. Include lone pair electrons. ← Draw an arrow from π to a pi bond 7. Answer the following from text pages 504-511: →50c__________________________________ →56a_________________________________________ →________________________________________________________________________________________80 Rewrite the sublimation equation and include the heat term on the proper side↑. Do not use ∆H notation. →________________________________ Calculate the amount of heat. 8. Answer the next 8 questions using the graph to the right. 30 →Complete the graph to the right: Label the vertical axis “Pressure (atm)”. →Write sol (solid), liq (liquid), and gas in the appropriate areas of the graph. 20 →Circle the triple point. →Draw a dotted line showing a gas condensing to a liquid and freezing to a solid at constant pressure. Label this line “GLS”. Do not include the triple point. → __________________ Write the freezing (melting) temperature (from GLS). 10 0 →Draw a solid line on the graph showing sublimation at constant pressure. Label this line “SUB”. Do not include the triple point. → Pc= __________________ 0 10 20 30 40 Temerature(oC) →Tc = ___________________ Write the critical pressure and temperature. 50 60