HW-5 - Rahman, Tarique – Homework 5 – Due: Oct 2 2007,...

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Unformatted text preview: Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout   1 1. Mg , Se 10. None of these 004 (part 1 of 1) 10 points Which of the compounds below has bonds with the most covalent character? Ca2 I3    2. Ca +  I −→ © ©© © ¨ ¨¨ ¨ § §§   £ § Ca + I + I + I © © ¨ ¨ § § 3+ © £© ¨ ¦¨ − − ¥ ¥¥ ¥ ¤ ¤¤ ¤ + ¢ + ¥ ¤ § £§ ¢ ¢¢ ¢ 1. Ca + I I I −→ − −→ 1. BeCl2 2. LiCl 3. MgCl2 GG 003 (part 1 of 1) 10 points Use electron-dot notation to demonstrate the formation of ionic compounds involving the elements Ca and I. ¥ ¦¥ ¤ £¤ ¢ £¢ ¡ G I G G G Ca+ + Ca+ + Ca+ + F G £G F F E D C 6. E(SO4 )3 9. Ca + Ca + Ca + I BB Ca + Ca + BB F £F BB 5. E2 (SO4 ) + + B £B A A 4. E2 (SO4 )3 A 8. Ca + Ca + I −→ 2− I 88 A A £A 77 3. E3 (SO4 ) 9 −→ 3− 8 8 7 7 Ca + I + I 8 8 7 7 2+ 8 £8 66 7 ¡7 55 2. E(SO4 )2 − 6 6 5 @ 5 7. Ca + 4 I + I 6 6 £6 5 5 ¦5 1. E3 (SO4 )2 4 −→ − −→ CaI2 −→ Ca2 I −→ Ca3 I 3 33 3 2 22 2 Ca + Ca + Ca + + 3 3 2 2 2+ 2+ 2+ I 3 ¦3 3− 3− I 1 1 0 0 6. Ca + Ca + Ca + 2 £2 ) ( ' I + I Ca3 I2 1 0 ) ( ' 002 (part 1 of 1) 10 points An element E has the electronic configuration [Ne] 3s2 3p1 . Write the formula of its compound with sulfate. 1 £1 & && 0 ¦0 & Ca + I & & + & ¦& 3. Mg 2+ ,O 2− % %% % 5. Ca + I % % £% $ 2. Mg2+ , S2− −→ − ## "" !! 2+ 2− −→ CaI −→ −→ # # " +I " ! +I # # " " ! Ca3+ +Ca3+ + I ! ! # £# " £" 2− 2−       4. Ca + Ca + ! £! I + I + £    ¦   ¦   £   £ 001 (part 1 of 1) 10 points Which of the following pairs of ions would have the greatest coulombic attraction in a solid compound?   Ca + I   3+  £   3. Ca + I −→ 3−  Ca   ¦   £ + I   2+  £ This print-out should have 26 questions. Multiple-choice questions may continue on the next column or page – find all choices before answering. The due time is Central time. 2− −→ CaI −→ CaI I 2− −→ −→ Ca2 I3  Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout 7. 18; 8 4. CaCl2 8. 17; 6 5. NaCl 9. 17; 7 005 (part 1 of 1) 10 points The lattice enthalpy of calcium bromide is the energy change for the reaction 1. Ca(g) + 2 Br(g) → CaBr2 (g) 2. CaBr2 (s) → Ca2+ (g) + 2 Br− (g) 3. Ca(s) + Br2 ( ) → CaBr2 (s) 4. CaBr2 (s) → Ca(g) + Br2 (g) 5. CaBr2 (s) → Ca(g) + 2 Br(g) 006 (part 1 of 1) 10 points How many valence electrons are in a O atom? 1. 4 2. 8 3. 16 4. 2 5. 6 007 (part 1 of 1) 10 points 2− The P anion has how many total electrons and how many valence electrons? 1. 16; 5 2. 15; 5 3. 16; 6 4. 16; 7 5. 15; 7 6. 15; 6 6. Ca 2+ 2 10. 17; 8 008 (part 1 of 1) 10 points What total number of valence electrons should appear in the dot formula for the chlorate ion ClO− ? 3 1. 30 2. 28 3. 26 4. 24 5. 32 009 (part 1 of 1) 10 points Which of the following is the best representation of the compound calcium sulfide? 1. None is appropriate because calcium sulfide is a covalent compound. 2− H H Q Q 2. 2 Ca , V V + S RR S S 3. Ca , + S WW 2− b b 010 (part 1 of 1) 10 points Which of the following is the correct Lewis formula for oxygen (O2 )? f S pp i f i ,2 g hg ee d d 5. Ca2+ , S X S aa ` X ` 4. 3 Ca2+ , 2 c Pc Y PY I PI − T UT 3− − Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout ” h” rr 3 OO OO q s s t t w w € €  ‚‚ 011 (part 1 of 1) 10 points Which of the following is the correct Lewis formula for acetylene (ethyne, C2 H2 )? 1. H H ‡ ‡ 012 (part 1 of 1) 10 points How many unshared electrons and bonding electrons exist around the central atom in ozone, O3 ? 1. one; six 2. two; two C C †† 3. H H C C C C ‰‰ 6. H C H “ C “ ’’ H ““ ’ ’ ’ ’  h   5. H C ‘ C ‘ ‰ H ‘‘ ‰‰ ‰ ‰‰ 4. ‰ ‰ ‡ H ‡‡ ‡‡ 2. H ‡ C ‡ C ‡ ‡‡ †† H 3. none; two 4. zero; eight 5. three; six 6. four; four 7. two; six 8. four; three 9. one; three 013 (part 1 of 1) 10 points Which of the following contains exactly one unshared pair of valence electrons? 1. NaCl — —— — †† …… ‰ ƒ O ƒ O H — — ƒ ‡ ˆ‡ ‰ ƒƒƒ ƒƒƒ  h „„ ƒ 8. —— — h— 10. — H — C C — — ‚‚ ‚‚ ‚‚ 7. OO —— – –– — h— – — h—   OO  v €€ ‚‚ € H – – € 6. –– – h– 9. – H – C C – – yy  v yx yx O €€ O –– – h– 5. • H •• • • • w OO yy w vw xx w 4. u OO u vu w vw u 3. 8. H C ” H ”” ” ” ” 2. u vu q 1. rr qq qq tt tt xx 7. H C C C Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout 2. SiH4 3. PH3 4. H2 S 5. C2 H4 014 (part 1 of 1) 10 points How many double bonds are present in the “best” resonance structure of the phosphate ion? 1. 1 2. 3 3. 2 4. 0 015 (part 1 of 1) 10 points How many lone pairs of electrons are on nitrogen in NF3 ? 1. ten 2. three 3. two 4. none 5. thirteen 6. one r hr ˜ 4 F Cl F Cl f dd ˜˜ ™™ ˜ ™™ kk kk mm mm r r u u e e g g j j 2. 3. 4. 5. h F Cl F Cl g f ¦f ee F Cl F Cl F Cl l g ¦g 7. 8. 9. 10. F Cl F Cl o nn l ¦l F Cl o ¦o 017 (part 1 of 1) 10 points Which of the following is the correct Lewis formula for boron trichloride (BCl3 )? p pp 1. Cl B Cl 2. Cl q q B q Cl q Cl ss qq 3. 8. twenty 016 (part 1 of 1) 10 points Which of the following is the correct Lewis formula for chlorine fluoride (ClF)? Cl r hr B tt Cl t u Cl uu u uu u u u hu 4. u Cl B Cl u uu s 7. four Cl t t p s h h l o t ii ii nn l ¦l o ¦o u hu jj jj h 6. ˜ f g dd f ¦f g ¦g ee ˜ 1. ˜˜ Cl Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout 5. 5 Cl vv Cl Cl B B x x ww Cl 2. by asserting that electrons in a double bond can delocalize (spill over) onto adjacent single bonds to make a bond and a half. 3. where there is more than one choice of location for a double bond as deduced from Lewis dot structures. The true bonding is the average over all possible double-bond locations. 8. Cl z z B z 018 (part 1 of 1) 10 points The CO2− ion has how many resonance con3 figurations? 1. 4 2. It does not exhibit resonance. 3. 3 4. 5 5. 2 019 (part 1 of 1) 10 points Resonance is a concept that describes the bonding in molecules 1. by asserting that double bonds “flip” or resonate between two locations in the molecule. | Cl || | || | | | h| 10. | Cl | B Cl 1. All of these are important. 2. A only 3. B only 4. None of these is important. 5. B and C only 6. A and B only 7. C only 8. A and C only 021 (part 1 of 1) 10 points How many resonance structures can be drawn for N2 O? Disregard any structure with formal charges other than 0, +1, and −1. 1. 3 2. 0 ‰‰ ‡ ˆ‡ ˆˆ † † | || { Cl {{ | ˆ| { C) −3 C +1 N +1 O  ‚‚ N O  {{ 9. ƒ „ƒ …… { Cl { B { Cl B) −1 C { +1 −1 ~~ N O } ˆ} € h€ Cl zz  {{ y Cl yy z ˆz y Cl z yy 7. y Cl y B y Cl y xx Cl y ˆy Cl yy x x 6. 020 (part 1 of 1) 10 points Which of the three Lewis structures is the most important? A) −2 C +1 0 | h| | Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout products. 3. 2 4. 1 022 (part 1 of 1) 10 points Calculate the formal charge on N in the molecule NH3 . 1. 4 2. 2 3. 0 4. 3 5. 1 023 (part 1 of 1) 10 points Estimate the heat released when 1-butene (CH3 CH2 CH CH2 ) reacts with bromine to give CH3 CH2 CHBrCH2 Br. Bond enthalpies are C H : 412 kJ/mol; C C : 348 kJ/mol; C C : 612 kJ/mol; C Br : 276 kJ/mol; Br Br : 193 kJ/mol. 1. 288 kJ/mol 2. 507 kJ/mol 3. 181 kJ/mol 4. 317 kJ/mol 5. 95 kJ/mol 024 (part 1 of 1) 10 points The heat energy released or absorbed by a chemical reaction is generally determined by the difference between 1. the energy that is released upon breaking the bonds in the reactants and the energy that is released upon making the bonds in the 026 (part 1 of 1) 10 points Bond energies are approximate because CH4 (g) + I2 → CH3 I(g) + HI(g) . 025 (part 1 of 1) 10 points Consider the reaction 6 2. the energy that is released upon breaking the bonds in the reactants and the energy that must be put in to make the bonds in the products. 3. the energy that must be put in to break the bonds in the reactants and the energy that is released upon making the bonds in the products. 4. the energy that must be put in to break the bonds in the reactants and the energy that must be put in to make the bonds in the products. Bond energy tables give the following values: C H : 411 kJ/mol I I : 149 kJ/mol H I : 295 kJ/mol C I : 213 kJ/mol The change in enthalpy for this reaction is: 1. +52 kJ/mol 2. +463 kJ/mol 3. There is no way to tell. 4. −52 kJ/mol 5. −97 kJ/mol 1. they are averages over a number of molecules. 2. we cannot measure them accurately. 3. we cannot calculate them accurately. Rahman, Tarique – Homework 5 – Due: Oct 2 2007, midnight – Inst: Vandenbout 4. they depend upon the physical state of the molecule, gas, liquid, or solid. 5. not all molecules burn in oxygen, making calorimetry difficult. 7 ...
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