Name: Student ID Number: Section Number:

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1 Name: Student ID Number: Section Number: VERSION A KEY Some useful constants and relationships: Specific heat capacities (in J/g. K): H 2 O (l) = 4.184; Al (s) = 0.900; Cu (s) = 0.387; Steel (s) = J = 1 L. atm 1 atm = 760 Torr 1J = 1kg. m 2 /s 2 1 ev = x J R = Ideal gas constant: L. atm. mol -1. K -1 = J. mol -1. K -1 Avogadro constant: x mole -1 Planck's constant = h = x J. s c = speed of light: 3.00 x 10 8 m/s R H = x 10-2 nm -1 C 2 = second radiation constant = 1.44 x 10-2 K. m q = C p mδt Tλ max = 1 5 C Emitted power (W) 2 = (constant)t 4 Surface area (m 2 ) e = mc 2 c = λν 1 λ = R 1 H 2 n 1 2 E = hν E = hc Z 2 E(in Joules) = n 2 λ n 2

2 1. Draw a Lewis structure for the one most important resonance form of the cyanate ion, NCO - and show the formal charges (6 pts). 3 points for correct Lewis structure, 3 points for correct indication of -1 formal charge on the singly bonded O atom. OK if they put 0 formal charges on N and C. This one was worked out in detail on pg. 312 of the text. 2. Circle the compound(s) that have a dipole moment (9 pts): PF 5 SF 4 PF 3 BF 3 CCl 4 CHCl 3 SF 4, PF 3, CHCl 3 3 pts each, all or nothing 3. In the ideal tetrahedral geometry, all bond angles are Is the H-N-H bond angle in NH 3 greater than or less than this value (circle one)? (5 pts) Less than (actual value is 107 ) 5 pts all or nothing 4. Draw valid VSEPR structures for the following compounds and indicate the idealized structure describing the geometry of the atoms. The first one is done for you. (30 pts) SnCl 2 PCl 4 + CH 2 F 2 IBr 3 V-shaped Tetrahedral Tetrahedral T-shaped ANSWER: 5 pts for each correct structure (focus on electron counts), 5 pts for each description of shape

3 Name: Student ID Number: Section Number: VERSION B KEY Some useful constants and relationships: Specific heat capacities (in J/g. K): H 2 O (l) = 4.184; Al (s) = 0.900; Cu (s) = 0.387; Steel (s) = J = 1 L. atm 1 atm = 760 Torr 1J = 1kg. m 2 /s 2 1 ev = x J R = Ideal gas constant: L. atm. mol -1. K -1 = J. mol -1. K -1 Avogadro constant: x mole -1 Planck's constant = h = x J. s c = speed of light: 3.00 x 10 8 m/s R H = x 10-2 nm -1 C 2 = second radiation constant = 1.44 x 10-2 K. m q = C p mδt Tλ max = 1 5 C Emitted power (W) 2 = (constant)t 4 Surface area (m 2 ) e = mc 2 c = λν 1 λ = R 1 H 2 n 1 2 E = hν E = hc Z 2 E(in Joules) = n 2 λ n 2

4 1. Draw a Lewis structure for the one most important resonance form of the thiocyanate ion, NCS - and show the formal charges (6 pts). 3 points for correct Lewis structure, 3 points for correct indication of -1 formal charge on the doubly bonded S atom. Note this is different from NCO- because O is more electronegative than N, and S is less electronegative than N. OK if they put (0) formal charges on S and C. See pg. 312 of the text. 2. Circle the compound(s) that have no dipole moment (9 pts): PF 5 SF 4 PF 3 BF 3 CCl 4 CHCl 3 PF 5, BF 3, CCl 4 3 pts each, all or nothing 3. In the ideal tetrahedral geometry, all bond angles are Is the H-N-H bond angle in NH 3 less than or greater than this value (circle one)? (5 pts) Less than (actual value is 107 ) 5 pts all or nothing 4. Draw valid VSEPR structures for the following compounds and indicate the idealized structure describing the geometry of the atoms. The first one is done for you. (30 pts) SnCl 2 BF 3 CH 3 Cl ICl 2 - V-shaped Trigonal planar Tetrahedral Linear ANSWER: 5 pts for each correct structure (focus on electron counts), 5 pts for each description of shape

5 Name: Student ID Number: Section Number: VERSION C KEY Some useful constants and relationships: Specific heat capacities (in J/g. K): H 2 O (l) = 4.184; Al (s) = 0.900; Cu (s) = 0.387; Steel (s) = J = 1 L. atm 1 atm = 760 Torr 1J = 1kg. m 2 /s 2 1 ev = x J R = Ideal gas constant: L. atm. mol -1. K -1 = J. mol -1. K -1 Avogadro constant: x mole -1 Planck's constant = h = x J. s c = speed of light: 3.00 x 10 8 m/s R H = x 10-2 nm -1 C 2 = second radiation constant = 1.44 x 10-2 K. m q = C p mδt Tλ max = 1 5 C Emitted power (W) 2 = (constant)t 4 Surface area (m 2 ) e = mc 2 c = λν 1 λ = R 1 H 2 n 1 2 E = hν E = hc Z 2 E(in Joules) = n 2 λ n 2

6 1. Draw a Lewis structure for the one most important resonance form of the ion NO 2 + and show the formal charges (6 pts). 3 points for correct Lewis structure, 3 points for correct indication of +1 formal charge on the N atom. Plus 1 formal charge on N because O is more electronegative than N. OK if they put (0) formal charges on O. This was homework problem 10.9 of the text. 2. Circle the compound(s) that have a dipole moment (9 pts): PF 3 SF 4 PF 5 BF 3 CCl 4 CHCl 3 PF 3, SF 4, CHCl 3 3 pts each, all or nothing 3. In the ideal tetrahedral geometry, all bond angles are Is the H-N-H bond angle in NH 3 less than or greater than this value (circle one)? (5 pts) Less than (actual value is 107 ) 5 pts all or nothing 4. Draw valid VSEPR structures for the following compounds and indicate the idealized structure describing the geometry of the atoms. The first one is done for you. (30 pts) SnCl 2 SF 4 IF 5 XeF 4 V-shaped See-saw or saw-horse Square pyramid Square planar ANSWER: 5 pts for each correct structure (focus on electron counts), 5 pts for each description of shape