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CHEM307 FALL 2003 Homework #1 CHEM311 Your Name:_______________________________ FALL 2005 Practice Exam #1 Signature:_________________________________ Instructions: This is a multiple choice / short answer PRACTICE exam. For the multiple-choice questions, there may be more than one correct answer. If so, then circle as many answers as you believe to be correct. You will get 3 pts for each correct response and –1 for each wrong response. If there is a choice of “other”, and you choose “other”, you MUST provide a correct alternative answer on the line provided in order to get the question right. Only choose “other” if there are no correct answers present. The short answer questions are worth 5 to 15 points each. Where I have asked for you to draw a structure or mechanism, be very precise with your arrows and such…don’t make me guess as to what you meant. You may only use a pen or pencil, big eraser, and a molecular model set to take this exam. You have 60 minutes to complete this exam. Your signature above indicates that you have taken this exam in accordance with the University Honor Code. Good luck! OH Compound A 1) A proper IUPAC name for Compound A is… a. 3-isopropanol-4-ethyl-4-heptyne b. 3,4-diethyl-3-hexen-2-ol c. 2-hydroxy-3-ene-bipentane d. semicycloheptenol e. other _______________________________________________ 2) Excluding alkyl groups, the main functional groups in Compound A are... a. alcohol, alkene b. alkyne, halide c. alcohol, ethyl d. aldehyde, halide e. other _________________________________________________ 3) Which below adequately describes the hybrdization states of the carbon atoms in Compound A? a. all are sp3 b. 4 are sp3, 4 are sp2, 2 are sp c. 4 are primary, 4 are secondary and 2 are sp2 d. 2 are sp2 and 8 are sp3 e. other _______________________________________________________ 1 4) What is the molecular formula of compound A? a. C10H22O b. C6H8OH c. C8H2OH d. C10H19O e. other ______________________________________________________ 5) A sigma bond… a. …is one in which the electron density lies in between the nuclei b. …allows for free rotation round the bond c. …results from the indirect overlap of p-orbitals d. …results from ionic interaction of s-orbitals e. other _______________________________________________________ 6) A pi bond… a. …has a nodal plane that cuts through the two nuclei b. … is one in which the electron density lies in between the nuclei c. …may allow for resonance structures of charged molecules to be drawn d. …results from small electronegativity differences between different carbons e. other ________________________________________________________ 7) A carbon-carbon double bond consists of… a. …2 sp2 hybridized carbon atoms b. …a sigma bond and a pi bond c. …a sigma bond and 2 pi bonds d. …an ionic bond and a sigma bond e. other ________________________________________________________ 8) A carbon-carbon triple bond… a. …consists of two carbons with sp hybridization b. …is longer than a C-C single bond c. …has linear geometry d. …consists of two sigma bonds and one pi bond e. other __________________________________________________________ 9) Which of the following are true? a. heptene has a molecular formula of C7H14 b. eicosane has 20 carbons c. cyclooctadienol has two OH’s d. 2-butyne is a linear molecule e. none are true. 10) Hexane is a common organic solvent. Which compound is likely most readily soluble in hexane and why? a. decane because it is a non-polar straight chain compound like hexane. b. cyclohexanol, because it is has six carbons like hexane. c. water, because it is a common solvent just like hexane. d. acetic acid, because that is how we make Italian dressing e. other ________________________________________________________ 2 11) Octanol is a common solvent, particularly in environmental research because it mimics the chemical properties of living tissue. Which compound is likely most readily soluble in octanol and why? a. cyclohexanol, because it can hydrogen bond like octanol. b. octadecane, because it has 18 carbons just like octanol c. water, because it is a common solvent found in environmental systems d. polyaromatic hydrocarbons, because both have lots of double bonds. e. other _______________________________________________________ Compound B = 3,4-diethyl-2,5-dimethyl-2,4-cyclopentadienol 12) Draw (with great precision) compound B. 13) The common name for compound B is... a. trimyristin b. alkylpentaneneol c. humenol (because it looks like a little person) d. Our professor is nuts…there is no common name, he/she just makes this @#$% up. e. Other __________________________________________________________ 14) The molecular formula of Compound B is… a. C11H18O b. C11H17O c. C9H20O2 d. C11H22O e. other _________________________________________________________ 15) Compound B has… a. two double bonds b. has 4 primary carbons c. has 2 secondary carbons d. has a molecular charge of –1 e. other __________________________________________________________ 3 16) I have just removed a hydride (H-) from the #1 carbon on compound B to make a cation at carbon number 1. Draw the cation and any two other resonance forms using the proper arrow notation (be precise). 17) When drawing resonance structures… a. …you are allowed to move hydrogens if necessary b. …you can only move electrons c. …you can move double bonds anywhere you deem necessary d. …you can only move electrons if they are in the longest continuous chain e. other ___________________________________________________________ 18) When naming organic compounds… a. …first number the compound b. …first find the longest carbon chain (or biggest ring) that contains the highest priority functional group c. …first locate all the halogens d. …first look up the common name on the internet e. other __________________________________________________________ 19) Carbon single, double and triple bonds have different bond lengths and strengths. Demonstrate to me that you understand why by completing the table below by assigning the hybridization states of the 2 carbons involved (e.g., sp2-sp3), giving me the % s and p character in the bond, and telling which is longest, shortest, strongest, etc. Bond type hybridization % s character % p character length strength single double triple 4.
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