Chemistry 1A, Spring 2009 Midterm Exam II, Extended Practice Version

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1 Chemistry 1A, Spring 2009 Midterm Exam II, Extended Practice Version Friendly Note: This extended practice midterm is intended to be more challenging than the real midterm, so do not feel frustrated when you cannot answer some or a lot of the questions, especially the conceptually based ones. In this practice, I attempted to pull together the majority of possible questions that could appear on the midterm. Those that I felt had a high probability of being on the midterm in some form have redundancies for practice, hence the unique column on the number of questions. Unfortunately, conceptual questions cannot truly be repeated, so hopefully you ll gain at least a decent understanding after undergoing the problem. A simple answer key to all the multiple-choice problems is provided at the end for you to compare your answers. Note that there may be problems that have incorrect answers, which may be due to my own question outsmarting me, or just a plain mistake on my part. If you can prove that your answer is correct through the textbook, then you re most likely correct. This also goes along with conceptual problems, since they are generally the most disputed types. There will be an extended answer key released later this week, hopefully before Friday evening, which will have explanations to each type of question. I cannot guarantee that your midterm grade will be higher after going through this practice exam, but I can promise that you will be, at the very least, decently prepared. I wish you all good luck on your second midterm! ~Stephen Kok ^^ Section Concentrations Discussion: Periodic Trends - Ionization Energy Discussion: Lewis Dot Structures I Determining the Likelihood of Existence Discussion: Lewis Dot Structures II Resonance Structures WebAssign Week 4 Textbook: Chapter 1 WebAssign Week 5 Textbook: Chapter 2 WebAssign Week 6 Textbook: Chapter 3 Part I WebAssign Week 7 Textbook: Chapter 3 Part II, Chapter 4 Experiment 3: Molecules and Light Experiment 4: How the Nose Knows Experiment 5: Molarity of a Strong Acid ChemQuizes Uncovered Questions Questions Unique Total

2 Discussion: Periodic Trends Ionization Energy 1) Regarding the energy involved in the ionization of an atom, which of the following statements is true? A) The energy released in ionization is constant for all elements and ions B) The energy consumed in ionization is constant for all elements and ions C) The energy consumed in ionization is constant for all elements, except for ions D) The energy consumed in ionization is proportional to the effective nuclear charge E) The energy released in ionization is proportional to the effective nuclear charge 2) Regarding the energy involved in the ionization of an atom, which of the following statements is true? A) The ionization energy increases with the successive ionization of an atom B) The ionization energy decreases with the successive ionization of an atom C) The ionization energy stays the same with the successive ionization of an atom D) The ionization energy may increase or decrease with the successive ionization of an atom E) None of the above 3) Regarding the energy of an atom after undergoing ionization, which of the following statements is true? A) The total energy of the atom increases relative to its original ground state B) The total energy of the atom decreases relative to its original ground state C) The total energy of the atom is equal to its original ground state D) The total energy of the atom may increase or decrease relative to its original ground state E) None of the above 4) Of the following elements, which one would exhibit a large increase in the required ionization energy in its 3 rd ionization? (From X 2+ X 3+ +e - ) A) Na B) Ca C) Al D) C E) N 5) Of the following elements, which one would exhibit a large increase in the required ionization energy in its 2 nd ionization? (From X 1+ X 2+ +e - ) A) K B) Mg C) B D) Si E) P 6) Of the following elements, which one would exhibit a large increase in the required ionization energy in its 5 th ionization? (From X 4+ X 5+ +e - ) A) Na B) Al C) Si D) P E) S 7) Regarding the ionization of a ground state atom of boron (B), which of its successive ionizations would require the least energy? A) 1 st B) 2 nd C) 3 rd D) 4 th E) 5 th

3 8) Regarding the ionization of a ground state atom of phosphorus (P), which of its successive ionizations would require the least energy? A) 1 st B) 2 nd C) 3 rd D) 4 th E) 5 th 9) Regarding the ionization of a ground state atom of magnesium (Mg), which of its successive ionizations would exhibit a large increase in the required energy? A) 1 st B) 2 nd C) 3 rd D) 5 th E) 6 th 10) Regarding the ionization of a ground state atom of sulfur (S), which of its successive ionizations would exhibit a large increase in the required energy? A) 2 nd B) 3 rd C) 5 th D) 7 th E) 8 th 11) Which of the following statements correctly explains a sudden increase in ionization energy regarding an atom undergoing successive ionization? A) There is no sudden increase in ionization energy; there is a steady linear trend B) The sudden increase is caused by neutrons interfering with the ionization process C) The sudden increase is caused by the interference of neutrons in the ionization process after a particular ionization phase D) The sudden increase is merely an anomaly that occurs randomly during ionization E) The sudden increase is caused by the relative increase in effective nuclear charge exerted over electrons after a particular ionization phase 12) Ionization energy typically increases as you A) Move right across a period and down along a group B) Move right across a period and up along a group C) Move left across a period and down along a group D) Move left across a period and up along a group E) Ionization energy does not exhibit a periodic trend 13) Arrange the following elements in order of increasing ionization energy: Ni, Ge, Ca, Se, Ti A) Ca<Ge<Ni<Se<Ti B) Se<Ge<Ni<Ti<Ca C) Ca<Ti<Ni<Ge<Se D) Se<Ti<Ge<Ca<Ni E) None of the above 14) Arrange the following elements in order of decreasing ionization energy: Si, Na, P, Mg, S A) Na>Mg>Si>P>S B) Na>Mg>S>P>Si C) S>P>Mg>Si>Na D) S>P>Si>Mg>Na E) None of the above 15) Arrange the following elements in order of increasing ionization energy: Sr, Mg, Be, Sr, Ba A) Be<Mg<Ca<Sr<Ba B) Be<Ba<Mg<Sr<Ca C) Ba<Ca<Mg<Be<Sr D) Ba<Sr<Ca<Be<Mg E) None of the above

4 16) Arrange the following elements in order of decreasing ionization energy: Na, F, Li,Cl,K A) F>Cl>K>Na>Li B) Li>Na>K>Cl>F C) Cl>F>Li>K>Na D) F>Cl>Li>Na>K E) None of the above Discussion: Lewis Dot Structures I Determining the Likelihood of Existence 17) Which of the following molecules is stable? A) NH 2 B) CH 4 C) CN D) H 3 O E) None of the above 18) Which of the following molecules is stable? A) OH B) ClO C) NO 2 D) SO 4 E) None of the above 19) Which of the following molecules is stable? A) HSO 4 B) HCO 2 C) H 2 O 2 D) H 2 AsO 4 E) None of the above 20) Which of the following elements typically form four bonds? A) F B) O C) N D) C E) None of the above 21) Which of the following elements typically form two bonds? A) C B) P C) Br D) Cl E) None of the above 22) Which of the following best completes this statement: Generally, an atom shares as many of its valence electrons as possible, until A) all the valence electrons are covalently bonded B) all the valence electrons are unpaired C) the atom completes its octet/duplet D) the atom no longer has a noble gas electron configuration E) None of the above Discussion: Lewis Dot Structures II Resonance Structures 23) Consider the sulfate ion (SO 4 2- ), which of the following bond lengths would be typically found? (Note that sulfate violates the octet rule) A) S O Single bond lengths B) S=O Double bond lengths C) S O / S=O Single and Double bond lengths D) A hybrid bond length between single and double bond lengths E) None of the above 24) A single bond between two oxygen atoms has a length of 1.48Ǻ, while a double bond has a length of 1.21Ǻ. However, ozone (O 3 ) has a bond length of 1.28Ǻ, explain this discrepancy.

5 25) Which of the following statements best describes the nature of a resonating bond? A) The particular bond constantly changes from one form to the next, which is the main reason for the need of resonance lewis dot structures. B) The bond is volatile where it is prone to change when exposed to energy, which shifts the shared electrons to another bonding location C) The bond does not exist as either form depicted in the resonance structures, it is actually a hybrid bond in which its length is between the two depicted bonds D) The resonating bond is representative of the varying locations the bond may appear at for the molecule, though it stays in one location for a single molecule E) None of the above 26) Draw the resonance structures of the carbonate ion (CO 3 2- ) 27) Draw the resonance structures of the formate ion (HCO 2 - ) 28) Draw the resonance structures of the oxalate ion (C 2 O 4 2- ) WebAssign Week 4 / Textbook: Chapter 1 29) Which of the following elements has the correct ground-state electron configuration? A) Mg [Ar] 3s 2 B) N [He] 2s 2 2p 3 C) Cl [He] 3s 2 3p 5 D) Si [Ne] 3s 2 4p 2 E) F [Ne] 2s 2 2p 5

6 30) Which of the following elements has an incorrect ground-state electron configuration? A) S [Ne] 3s 2 3p 4 B) C [He] 2s 2 2p 2 C) Be [He] 2s 2 D) Ca [Ar] 4s 2 E) Na [Ne] 2s 2 31) Which of the following elements has the electron configuration [He] 2s 2? A) He B) Li C) Be D) H E) B 32) Which of the following elements has the electron configuration [Ne] 3s 2 3p 3? A) P B) N C) S D) O E) Ne 33) In ionization from their ground-state, which of the following elements would have an electron removed from the 3p orbital? A) He B) F C) Be D) Cl E) Mg 34) Through ionization, which of the following ions would have an electron removed from the 2p orbital? A) Be 2+ B) F - C) Mg + D) B 2+ E) Al + 35) Through ionization, which of the following ions would have an electron removed from the 3p orbital? A) Al 3+ B) S 3- C) Ca + D) Si 2+ E) K + 36) Of the following elements, which one contains a different number of valence electrons? A) Se B) Br C) F D) Cl E) I 37) Of the following elements, which one contains exactly five valence electrons? A) B B) F C) As D) S E) Si 38) How many unpaired electrons does the ground-state atom of phosphorus (P) have? A) 0 B) 1 C) 2 D) 3 E) 4 39) Of the following elements, which one contains unpaired electrons in its ground-state? A) S B) Mg C) He D) Ca E) Ne 40) Of the following elements, which one contains exactly two unpaired electrons? A) N B) Se C) Cl D) Ar E) Al 41) Order the following ions from smallest to largest radii: B 3+, N 3-, Be 2+, O 2-, Li +, F - A) B 3+ < Be 2+ < Li + < F - < O 2- < N 3- B) B 3+ < N 3- < Be 2+ < O 2- < Li + < F - C) N 3- < Li + < O 2- < Be 2+ < F - < B 3+ D) N 3- < O 2- < F - < Li + < Be 2+ < B 3+ E) N 3- < B 3+ < O 2- < Be 2+ < F - < Li +

7 P D) P P 42) Order the following ions from largest to smallest radii: As 3-, Ga 3+, Se 2-, Ca 2+, Br -, K + A) Ga 3+ < As 3- < Ca 2+ < Se 2- < K + < Br - B) Ga 3+ > Ca 2+ > K + > Br - > Se 2- > As 3- C) As 3- < Ga 3+ < Se 2- < Ca 2+ < Br - < K + D) As 3- > Se 2- > Br - > K + > Ca 2+ > Ga 3+ E) As 3- < K + < Se 2- < Ca 2+ < Br - < Ga 3+ 43) Which of the following statements regarding the electrons on a nitrogen atom in the ground state is true? A) Z eff for an electron in a 1s-orbital is the same as Z eff for an electron in a 2s-orbital B) Z eff for an electron in a 2s-orbital is the same as Z eff for an electron in a 2p-orbital C) An electron in the 2s-orbital has the same energy as an electron in the 2p-orbital D) The electrons in the 2p-orbital all have the same spin quantum numbers m s. E) The electrons in the 2s-orbital have the same value for the quantum number m s ) Which of the following valance-shell configurations represents the ground state for a neutral atom? A) s. B) s. C) s. p s. E) None of the above 45) Order the following elements by increasing electron affinity: Si, S, Al, Cl A) Cl<S<Si<S B) Si<S<Al<Cl C) Al<Si<S<Cl D) Al<S<Si<Cl E) Cl<Al<S<Si 46) Order the following elements by decreasing electron affinity: Br, I, At, F, Cl A) F>Cl>Br>I>At B) F>Br>Cl>I>At C) I>F>Br>Cl>At D) At>I>Br>Cl>F E) At>Br>I>Cl>F WebAssign Week 5 / Textbook: Chapter 2 47) Which of the following ions has an incorrect ground-state electron configuration? A) Mg + [Ne] 3s 1 B) N 3- [Ne] C) Cl - [Ar] D) Si 2- [Ne] 3s 2 3p 4 E) F 2- [Ne] 2s 1 48) Which of the following ions has the correct ground-state electron configuration? A) S 3- [Ne] 4s 1 B) C - [He] 2s 2 2p 3 C) Be 3+ [He] D) Ca + [Ar] 4s 2 E) Na 2+ [Ne] 2s 2 2p 5 49) Determine the formal charge of each atom in formaldehyde (HCHO) A) H 0, C +1, O -1 B) H +1, C 0, O -1 C) H 0, C +2, O -2 D) H 0, C 0, O 0 E) H 0, C -1, O +1

8 50) Determine the formal charge of each atom in the ammonium cation (NH 4 + ) A) N +1, H 0 B) N -3, H +1 C) N 0, H 0 D) N -1, H 0 E) N +2, H -1 51) Determine the formal charge each atom in carbon monoxide (CO) A) C +1, O -1 B) C -1, O +1 C) C 0, O 0 D) C +2, O -2 E) C 0, O 1 52) Which of the following molecules is a radical? A) Cl 2 O B) N 2 O C) BrO D) COCl 2 E) BF 4-53) Order the following molecules in terms of increasing bond order of the NO bond(s) in: NO -, NO - - 2, NO 3 A) NO - < NO < NO 3 B) NO - 3 < NO - 2 < NO - C) NO - 2 < NO - 3 < NO - D) NO - 3 < NO - - < NO 2 E) NO - = NO = NO 3 54) Order the following molecules in terms of decreasing bond order of the CO bond(s) in: CO 3 2-, CO 2, CO A) CO 3 2- > CO > CO 2 B) CO 2 > CO 3 2- > CO C) CO 3 2- > CO 2 > CO D) CO > CO 2 > CO 3 2- E) CO = CO 2 = CO ) Order the following molecules in terms of increasing bond order of the single NO bond in: CH 3 NH 2, CH 2 NH, HCN A) CH 3 NH 2 < CH 2 NH < HCN B) HCN < CH 2 NH < CH 3 NH 2 C) CH 2 NH < HCN < CH 3 NH 2 D) HCN < CH 3 NH 2 < CH 2 NH E) CH 3 NH 2 = CH 2 NH = HCN 56) Arrange the following cations in order of increasing polarizing power: Ca 2+, Na +, Be 2+, K +, Al 3+ A) K + < Na + < Ca 2+ < Be 2+ <Al 3+ B) Al 3+ < Be 2+ < Ca 2+ < Na + < K + C) Na + < K + < Be 2+ < Ca 2+ <Al 3+ D) Al 3+ < Ca 2+ <Be 2+ < K + < Na + E) K + = Na + < Ca 2+ = Be 2+ <Al 3+ F) Al 3+ < Be 2+ = Ca 2+ = Na + < K + 57) Of the following elements, which ones are the most and least electronegative? (most, least) N, C, F, O, B A) (N, F) B) (O, B) C) (F, N) D) (F, B) E) (B, F) 58) Of the following elements, which ones are the most and least electronegative? (most, least) Bi, Se, Cl, Sb, O A) (Se, Sb) B) (O, Bi) C) (Cl, Bi) D) (O, Sb) E) (Cl, Se)

9 59) When faced with multiple possible Lewis dot models for a particular model, which of the following guidelines should be used to determine the most accurate model? A) The partial charges of the atoms should be minimized B) The element with the highest electronegativity should have a negative partial charge given that partial charges exists. C) The central atom should generally be the element with the lowest ionization energy D) The total formal charge of the molecule should match the overall charge of the molecule. (e.g. Neutral molecule = 0 charge, Polyatomic ion 0 charge) E) All of the above 60) Draw the Lewis dot structures for the following molecules and identify the overall dipole moment of the molecule if it exists. (Hint: Rule-breakers) SF 6 BrF 5 ClF 3 PCl 6-61) Based on your knowledge about bond lengths, which of following bond types would have the weakest strength? A) Single bonds ( ) B) Double bonds (=) C) Triple bonds ( ) D) They are equal in bond strength E) Depends on the atoms being bonded WebAssign Week 6 / Textbook: Chapter 3 Part I 62) Which of the following molecular shapes correctly classifies the molecule SO 2? A) Tetrahedral B) Trigonal Planar C) Linear D) Bent E) Trigonal Pyramidal 63) Which of the following molecular shapes correctly classifies the molecule BrF 5? A) Octahedral B) Square Pyramidal C) Square Planar D) Trigonal Bipyramidal E) T-shaped 64) Which of the following molecular shapes correctly classifies the molecule ClF 3? A) See-saw B) Bent C) Square Planar D) Trigonal Bipyramidal E) T-shaped

10 65) Which of the following molecular shapes correctly classifies the molecule SF 4? A) T-shaped B) Trigonal Bipyramidal C) See-saw D) Bent E) Square Planar 66) Which of the following molecular shapes correctly classifies the molecule PCl 5? A) See-saw B) Bent C) Square Planar D) Trigonal Bipyramidal E) T-shaped 67) Which of the following molecules is polar? A) CH 2 Cl 2 B) CCl 4 C) CH 4 D) SF 4 E) A and D 68) Which of the following molecules is nonpolar? A) CS 2 B) PCl 3 C) ClF 3 D) BrF 5 E) C and D 69) Which of the following molecules is nonpolar? A) CClF 3 B) TeF 4 C) COF 2 D) XeF 2 E) B and D For questions 70-74, match the appropriate molecular shape to the designated bond angle(s) 70) 90 A) Trigonal Planar 71) B) Trigonal Biypyramidal 72) 180 C) Linear 73) 90 and 120 D) Octehedral 74) 120 E) Tetrahedral WebAssign Week 7 / Textbook: Chapter 3 Part II, Chapter 4 For questions 75-79, match the molecular shapes to the hybridization required of its orbitals 75) Tetrahedral A) sp 76) Trigonal Biyramidal B) sp 2 77) Octahedral C) sp 3 78) Linear D) sp 3 d 79) Trigonal Planar E) sp 3 d 2 80) Considering that hybridized orbitals is a blend of the atomic orbitals, such as s, p, and d; as the contribution of the s orbital to the hybridized orbitals decreases, how would the bond angles molecular shape change? (Hint: A sp 2 hybridization orbital is approximately 33% s ) A) Bond angles typically increase B) Bond angles typically decrease C) Bond angles stay the same D) No change E) Variable change depending on the hybridization

11 For questions 81-84, use the following molecular orbital energy diagram of nitric oxide NO 4σ * 2π * E 2p 2p 3σ 1π 2s 2σ * 2s Nitrogen Atomic Orbitals Molecular Orbitals 1σ Oxygen Atomic Orbitals 81) Complete the molecular orbital energy diagram. 82) Is NO paramagnetic or diamagnetic? Explain your reasoning. 83) What is the bond order of NO? (Show your work) 84) NO is very reactive. Explain its reactivity in terms of its Lewis Dot Structure.

12 For questions 85-88, use the following molecular orbital energy diagram of hydrogen fluoride σ * HF E 1s 2p x,2p y (n.b.) 2p σ n.b. - non-bonding 2s (n.b.) 2s Hydrogen Atomic Orbitals Molecular Orbitals Fluorine Atomic Orbitals 85) Complete the molecular orbital energy diagram. 86) Is HF paramagnetic or diamagnetic? Explain your reasoning. 87) What is the bond order of HF? (Show your work) (Hint: Note the non-bonding orbitals) 88) Hydrogen contributes more to the sigma anti-bond, while fluorine contributes more to the sigma bond. Explain why this occurs.

13 89) If HF and NO undergo ionization, which of the molecules become more stable? Explain your reasoning. 90) If HF and NO undergo electron capture, which of the molecules have a shorter bond? Explain your reasoning 91) Given their ground-state electron configurations, which molecule would most likely exhibit a higher electron affinity? Explain your reasoning. 92) Given their ground-state electron configurations, which molecule would most likely exhibit a lower ionization energy? Explain your reasoning. 93) Suppose that 6.54 L of helium at a pressure of 1.21 atm is transferred to a vessel of 4.35 L whilst keeping the temperature of the gas constant. What is the final pressure of helium? Show your work.

14 94) If 2.13 moles of ideal gas molecules at 253 K and 0.95 atm in a closed container of constant volume were heated to produce a new pressure of 1.32 atm, what was the new temperature? Show your work. 95) In a particular experiment, 168cm 3 of hydrogen gas at atm and 24 C was observed within a vessel, however, measurements from a machine were taken at 1.01 atm and an unknown temperature, recording 142cm 3 of hydrogen instead. What temperature did the machine measure the hydrogen gas at? Show your work. 96) Another machine, probably from the same company, was also noted to give measurements at a different ambient temperature and pressure, specifically, 1.21 atm and 35 C. Given that the hydrogen gas used in this experiment had a volume of 3.23L at 1.02 atm and 20 C, what was the reading given by this machine? Show your work.

15 Experiment 3: Molecules and Light Use the following graph to solve question 97 Absorbance Absorbance of Sample Concentration mol/l 97) What would be the approximate the absorbance reading for a 0.5M sample? A) 0.55 B) 0.45 C) 0.35 D) 0.25 E) Not enough information 98) Given a data reading from this experiment (0.43 mol/l, 0.37), estimate the extinction coefficient for this sunscreen. Show your work. (Assume l=1cm) 99) If you accidently programmed the spectrometer to 580nm rather than 310nm, what information would you get from the absorbance readings? 100) Explain the reason for putting a blank solution of solvent into the spectrometer.

16 Experiment 4: How the Nose Knows 101) If butyl ethanoate, as shown in the box, smells fruity, which one of the following compounds is also likely to smell fruity? O Butyl Ethanoate O O O N O O N O A B C D E OH 102) Explain your reasoning to the best of your knowledge of smells Experiment 5: Determination of the Molarity of a Strong Acid Questions 103 and 104 are interrelated 103) You are experimentally determining the concentration of an unknown acidic solution. Using g of TRIS, you create a basic solution with 45.63mL of distilled water. In the burret contains the unknown acidic solution, which you use to titrate the basic solution until the endpoint, where the indicator turns green. This occurs at 26.35mL. What is the concentration of the acidic solution? (TRIS molar mass = g/mol) Show your work.

17 104) In the previous experiment, you had misread the scale and recorded g of TRIS rather than the correct amount of g. How does this impact your calculated concentration? Show your work. Questions are interrelated 105) Suppose your are determining an unknown basic solution s concentration. Using 30 ml of 0.43M HCl, you decide to titrate the solution with an indicator. The HCl sample is initially yellow, due to the indicator, and at 42.23mL, the indicator changes to a light shade of green. Using the data provided, determine the concentration of the basic solution. Show your work. 106) In the previous experiment, you had mistakenly forgotten to swirl the beaker during the titration. With a simple swirl of the beaker with the acidic basic mixture, the solution turns yellow again. You had already disposed of your basic solution and cannot titrate any further. How does this error affect your calculated concentration of the basic solution? Explain your reasoning. 107) Suppose the basic solution had been diluted beforehand, where a 7.5mL sample of the stock solution was diluted in a 300mL volumetric flask. Using the information from the titration, determine the concentration of the stock basic solution. Show your work.

18 108) A fellow classmate asks you to help them determine the precision of her data in his recent titration experiment. Determine the percent differences for all three trials. Show your work. Trial M Trial M Trial M ChemQuizes: Uncovered Questions 109) Of the following elements, which atom does not change in terms of energy when a valence electron s spin is reversed? A) Si B) As C) B D) O E) Ca 110) Given that the neutral sodium (Na) atom has an ionization energy of 496 kj/mol and an electron affinity of -53kJ/mol, what is the electron affinity for Na +? A) -496 kj/mol B) -53 kj/mol C) 496 kj/mol D) 53 kj/mol E) -443kJ/mol 111) For which element (X) does the following reaction release the most energy? Na + + X NaX A) F - B) Cl - C)Br- D) I- E) At - 112) Which element (X) would form a fluoride (X? F? ) that is ~30% F by mass? A) Sr B) Rb C) Ca D) K E) Na 113) How many structural isomers are there of the hydrocarbon butane (C 4 H 10 )? A) 1 B) 2 C) 3 D) 4 E) 5 114) How many structural isomers are there of the hydrocarbon hexane (C 6 H 14 )? A) 2 B) 3 C) 4 D) 5 E) 6

19 115) Which of the following molecules is chiral? H H H Cl H H 3 C C CH 2 CH 3 Cl C C CH 3 Cl C C CH 3 Br Cl H Br (A) (B) (C) CH 3 Br F H C CH 2 CH 3 CH 3 C CH 3 Br Br (D) (E) 116) Which is the energy diagram for sulfur hybrid atomic orbitals in SF 6? 3s 3p 3d (A) (B) (C) (D) (E) 117) A mixture of 2.0 atm of C 2 H 6 and 1.5 atm of O 2 react in a 5L flasks at a constant high temperature. What happens to the total pressure in the system? (Assume complete reaction) 2C 2 H 6 + 7O 2 4CO 2 + 6H 2 O A) Increases B) Decreases C) Stays the Same D) Depends on the constant temperature E) Not enough information to decide 118) Two moles of chlorine atoms occupies ~12.2L at 0.40 atm and 357K. What is the molecular formula of the chlorine? A) Cl 2 B) Cl 4 C) Cl 8 D) Cl 10 E) Cl 12

20 Simple Answer Key (Boxes without answers denote free-response questions that will be covered in the extended key) 1 D 21 E 41 A 61 A B 2 A 22 C 42 D 62 D B 23 D 43 D 63 B B B 64 E A 25 C 45 C 65 C C A 66 D A E 67 E A B 68 A C 29 B 49 D 69 D C 10 D 30 E 50 A 70 D A 11 E 31 C 51 B 71 E A 12 B 32 A 52 C 72 C A 13 C 33 D 53 B 73 B B 14 D 34 B 54 C 74 A D 15 E 35 E 55 A 75 C A 16 D 36 A 56 A 76 D B 17 B 37 C 57 D 77 E 97 B 117 A 18 E 38 D 58 B 78 A E 19 C 39 A 59 E 79 B D 40 B B