practiceexam1_answ_S20

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What wavelength(s) does methyl orange absorb the least? Include units. What color(s) does methyl orange absorb the least?

In IR absorption spectra of a compound, strong absorptions at 3300 cm and 2100 to 2260 cm were observed. What functional group might the compound contain? a. Alkyne b. Alkene с. Alcohol d. Carboxylic acid

The following NMR and IR spectra were obtained for a molecule with molecular formula C2H4O2. Draw the structure of the molecule that is consistent with the two spectra. Note. In the NMR spectrum, s stands for singlet. LOD C2H,O2 3H, s 3000 cm-1 1H, s 1720 cm-1 D 4000 3000 2000 1500 1000 HAVENUMBERI l 12 10 8 4 -2

True or False 1. A molecule that is "IR inactive" means that it does not produce any signal due to no vibration. 2. Infrared spectroscopic data is reported in wavenumber (cm-1) against absorbance because they have a linear relationship. 3. The signals observed from a molecule of chloropropane will have a higher wavenumber than iodopropane. 4. The signals observed from the C-C bond in an alkene will report at a higher wavenumber than the C-C bond in an alkyne.

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Which of the following molecules: A. H₂C 0 CH₂ C. Ï_¶Ï H₂C B. H₂C A. acetone C. ethanol OH B. methyl acetate E. ethyl acetate D. diethyl ether is best represented by NMR spectra below? D. 20 H.C 17122 .CH₂₁ 14 E. H₂C 10 20 13C

Which of the indicated carbon atoms in each molecule absorbs farther downfield? a. CH,CH2OCH,CH3 b. BRCH,CHBr2 d. CH,CH=CH2 C. f OCH,

3. How does the infrared spectrum of methylenecyclohexane differ from 1-methylcyclohexene?

Question 6 of 17 Consider a molecule with the molecular formula of C10H13 NO2. The IR and ¹H NMR spectra are shown below. Draw the structure that best fits this data. 4000 3000 11 2000 10 1500 Wavenumbers (cm) + Submit 1000 ZI 2H2H select to Draw 500 Q

Organic chemistry 2: from the attached NMR spectrum what can be the proposed molecule that corresponds to the spectrum. Please discuss how how you arrived at the identity of the compound.

2. Determine the structure of a compound with a molecular formula of C6H120 and exhibits the following 'H NMR and 1°C NMR spectra. No peaks exchange in D20. | = 6 = 3 200 100 0.0 13 C NMR 1.1 1.0 | = 2 | = 1 %3D 2.6 2.5 2.4 9.0 8.0 7.0 6.0 5.0 4.0 3.0 2.0 1.0 0.0 1 H NMR

A couple questions using H-NMR and IR spectroscopy.

A3.

The IR and 13C NMR spectra are shown for a molecule with the molecular formula of C5H10O. Draw the structure that best fits this data.

How can IR spectroscopy be used to distinguish between the following compounds?a. a ketone and an aldehydeb. a cyclic ketone and an open-chain ketonec. benzene and cyclohexened. cis-2-hexene and trans-2-hexenee. cyclohexene and cyclohexanef. a primary amine and a tertiary amine

12) infrared spectra and 1H NMR spectra for each compound are provided on this and the next Compounds A, B, and C were found to have a molecular formula CaHsO2. The page. Determine the structural formula of each compound. IHD = Compound A 6 H Compound A 1 H 11 10 Compound B 3 H Compound B Kexchanges with D20) 2 H 1 H 10 Compound C ff 口 Compound C 3H 1 H 2H 2 H 10

Transmitance 1.2 1.0 0.8 0.6 0.4 0.2 0.0 3500 3000 2500 2000 1500 1000 500 Wavenumbers (cm-1)

Infrared Spectroscopy (IR) is very useful for determining the functional groups present in an organic molecule. For each of the spectra below, complete the following: • Build the molecule in Spartan and describe the motion of the molecule at each key absorption frequency • Identify key absorption frequencies in the spectrum and identify the type of stretch/bend/wag/etc. (i.e. O-H) • Match the spectra from the provided structures • Identify the main functional groups in the molecule OH A B F D E H OH NH2 J

Which of the following compounds has a UV spectroscopic signal at the lowest absorption energy? II IV A. I B. II C. II D. IV

Pls explain too

5.) Determine and draw the structure corresponding to the spectral information provided below. Explain what clues you used to determine the structure.

8. A strong signal in infrared spectroscopy indicates that a molecule matches the emitted electromagnetic radiation and reports a high transmittance. True False 9. The signals observed from the C-C bond in an alkene will report at a higher wavenumber than the C-C bond in an alkyne. True False 10. The electronegativity difference present in a dipole moment within a bond is directly proportional to the electromagnetic field produced. True False

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Which atom do you expect is present in this spectrum? 100 Rel. Intensity 80 60 60 40 40 20 20 0.0 0.0 15 30 45 60 75 90 m/z NIST Chemistry WebBook (https://webbook.nist.gov/chemistry) Only hydrocarbons Bromine Chlorine O Nitrogen

Match the four structures with the four IR spectra (by putting a proper letter in the box to the right of each spectrum). Use specific IR absorptions for various functional groups to identify the structures. Circle the important peaks in each spectrum that helped you identify the functional group(s) and label the functional group beside it.

Thx

Following are 1H and 13C spectra for each of three isomeric bromoalkanes with formula C4H9Br. Assign a structure to each pair of spectra.

Consider a molecule with the molecular formula of C7H12O. The IR and 'H NMR spectra are shown below. Draw the structure that best fits this data. 4000 3000 2000 1500 1000 500 Wavenumbers (cm) + зн 3H 3H 2H 1H 2 ppm of

Consider a molecule with the molecular formula of C3H7NO2. The IR and ¹H NMR spectra are shown below. Draw the structure that best fits this data. 4000 3000 2H 2000 1500 Wavenumbers (cm-¹) + 2H 1000 3H 500 ppm