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Name Last First Instructor O Bliem Exam Classroom O Curtis ONYEN O Dempsey O Fostvedt CHEM 101 Practice Exam II DO NOT OPEN OR WRITE ANYTHING UNTIL INSTRUCTED TO DO SO Instructions 1 Write your name and ONYEN e g bliem above write your ONYEN at the top of each page 2 Do NOT remove the staple or tear off the front page 3 Read each question carefully 4 Multiple choice many select questions can be answered in pencil 5 For many select questions mark x in checkboxes no stray marks 6 All other questions must be written in pen 7 SHOW YOUR WORK with correct units and sig figs Partial credit based on work shown 8 Use the periodic table 9 Double check your calculations 10 ANSWERS MUST BE PLACED IN THE BOXES or LINES including CORRECT UNITS and sig figs 11 Do not leave any answers blank 12 Read and sign the honor pledge when and only when you finish taking the exam 13 As part of the Honor Code you may not discuss contents of this exam with peers until the exam has been returned to you 14 Return all pages when you complete the exam 15 Relax You ve got this Honor Pledge By signing below I pledge that I have not violated the UNC Honor Code by receiving or giving unauthorized assistance on this exam If I do not sign then I acknowledge that I was not honorable in taking the exam and understand that it will simply not be graded no questions asked Signature 101 ONYEN 1 mL 1 cm3 h 6 626 10 34 J s h mv 1 000 mol 6 022 x 1023 1 10 10 m c 2 998 108 m s E h c E hc 1 2 1 2 where hcRH 2 18 x 10 18 J Eel Q Q d 1 661 x 10 24 g 1 000 amu 2 ONYEN Multiple Choice 5 points each 1 In which of the following atoms does the 3s subshell have the smallest diameter 2 What concept explains why the first ionization energy of Mg is so much smaller than the first ionization energy of S O A Effective nuclear charge O B Repulsion between two electrons occupying the same orbital O C Increasing quantum numbers O D Electron affinity 3 Order the following atoms from highest to lowest electronegativity O A Ca O B K O C Cl O D Br Li C N F Cs O A Li C N F Cs O B F N C Li Cs O C Cs Li C N F O D F N C Cs Li energy O A Sr3N2 O B BaI2 O C CaS O D Ca3N2 O E BaS 3 4 From the following ionic compounds which do you expect to have the most negative lattice 5 Rank the following bonds in order of increasing length C O ONYEN O A C S C C C O C C C S O B C C C O C S O C C O C S C C O D C O C C C S O E C C C S C O 6 In the combustion reaction of methane CH4 what is the change in hybridization of the carbon from reactant to product CH4 g 2 O2 g CO2 g 2 H2O l 7 How many unhybridized p orbitals are on the carbon in H2CO O A sp2 to sp3 O B sp3 to sp O C sp3 to sp2 O D sp4 to sp2 O A 0 O B 1 O C 2 O D 3 4 ONYEN Blank page for scratch work 5 ONYEN 8 3 pts each Carefully determine whether each of the following statements is True or False B False some statements have multiple components that could be true or false You are encouraged to write your work as you analyze each statement I Compare IE3 of Ga and IE3 of Ca IE3 of Ga is greater than IE3 of Ca because the Zeff of Ga is greater than the Zeff of Ca A True The radius of I is larger than the radius of Xe because Xe has more protons in its nucleus A True I is larger than Br because of increased electron electron repulsion in the valence shell B False B False II III A True 9 8 pts Consider the polar covalent C Cl bond In the bond C has electron density than A less B more Cl because Cl has a giving C a charge A lower A electron affinity B higher B electronegativity A negative B positive C partial negative D partial positive 10 5 pts Rank the following species in order of increasing number of unpaired valence electrons and circle or in between each box below Ti2 Fe3 Ca 6 ONYEN II Short Answer Provide your answers to each part of the following questions within the box provided Be sure to show all work to be eligible to receive partial credit 11 8 pts The chlorine nitrate molecule ClNO3 is implicated in the destruction of the ozone layer over Antarctica Draw the best Lewis structure using the skeletal structure below and indicate formal charges in the table below OC Cl OA N OB Best Lewis Structure Add formal charges here Additional rows are provided if your best Lewis structure has multiple resonance structures You may not need all rows Label your structures above to match the rows Cl OA OB OC N 7 1 2 3 4 ONYEN 12 9 pts Provide the formula or the name for each of the following Name Formula Dinitrogen tetroxide Al2S3 Ammonium Chlorate 8 ONYEN 13 A 19 pts Draw the best Lewis Structure for each of the following ions best formal charges and provide electronic geometry and molecular shape of each ion Then determine if the ion is polar or not polar by circling the correct word BrO3 BrO4 BrO2 Electron domain geometry Molecular shape Polar or Not Polar Electron domain geometry Electron domain geometry Molecular shape Molecular shape Polar or Not Polar Polar or Not Polar B 4 pts Rank the three ions in order of increasing bromine oxygen bond length C 3 pts Consider the BrO3 ion does a single Lewis Structure adequately describe the bonding in BrO3 O A Yes because it describes how electrons are shared between atoms O B No because there are multiple ways that the electrons could be shared between atoms O C No because it is an ion with a 2 charge O D No because bromine does not have an octet 9 ONYEN Blank page for scratch work 10


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