Psychology

CHEM LAB MIDTERM PRACTICE

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CHEM LAB MIDTERM PRACTICE
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    1 PART 1 : Fill in the table below for each molecule, as demonstrated in the EXAMPLE. Please label equivalent protons with the same subscript letter, in alphabetical order, from left to right or clockwise when possible (as shown in the EXAMPLE). This assignment is to be completed independently.   H A H B H C H D H E H F H G Integration  6 4 4 Splitting (s,d,t,q…)  t q s Degrees of unsaturation  0 3 H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation2)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation3)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation4)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation5)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation1)CH 2 Cl 2 Draw expanded structure and label ALL protons accordingly EXAMPLE Draw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordingly CH 3 CH 2 F Draw expanded structure and label ALL protons accordingly CH 3 CH 2 CH 3 Draw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordingly # of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum OOC 6 H 14 O 2 C 5 H 10 Br ClC 6 H 10 BrCl OOH B  H B  H C  H C H C  H C H B  H B H A H A H A H A H A H A    2 6)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation7)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation8)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation9)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation10)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation11)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation Draw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordingly # of unique signals in 13 C-NMR spectrum Draw expanded structure and label ALL protons accordingly # of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum OOC 4 H 8 O 2 NC 9 H 21 N OOBrC 8 H 9 BrO 2 NNFC 10 H 15 FN 2 OOOOC 8 H 14 O 4 FC 4 H 9 F    3 12)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation13)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation14)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation15)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation16)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation17)H A H B H C H D H E H F H G IntegrationSplitting (s,d,t,q…)Degrees of unsaturation Draw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordingly # of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum Draw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordinglyDraw expanded structure and label ALL protons accordingly # of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum# of unique signals in 13 C-NMR spectrum OOOC 7 H 16 O 3 F FF FF FF FF FFFFFFFC 7 F 16 OOOOOOC 12 H 12 O 6 OHC 9 H 12 O SOC 6 H 4 OS CClNCl ClC 8 H 8 Cl 3 N    4 PART 2 : For each set of data on page 5-7, calculate and record the degree of unsaturation. Then use your problem solving skills to determine what chemical structure is consistent with ALL of the data on each page. You are not required to label the spectra (but feel free to do so). This assignment is to be completed independently. Suggestion for a general method to determine a chemical structure based on the provided molecular formula, IR, 1 H-NMR and 13 C-NMR spectroscopy data: 1.   Determine the degrees of unsaturation (understand what constitutes a degree of unsaturation and how to calculate it for molecules composed of C, H, O, S, N, Cl, Br, F, I). 2.   Identify possible/likely functional groups based on the data (especially IR and 1 H-NMR spectra). 3.   Identify evidence of symmetry in the molecule (many equivalent carbons or protons is a good indicator of symmetry in the molecule) 4.   Construct a molecule that is consistent with ALL pieces of the provided data. After constructing a molecule, re-check it, and make modifications as necessary. It is possible, although extremely rare, that more than one structure is considered consistent with the provided data and would receive full credit.  Notes on determining a chemical structure based on provided spectroscopy data. 1.   The same tables as used during the Spectroscopy Experiment (from the Jones textbook) should be consulted for this assignment and will be provided on the Final Laboratory Exam. However, do not interpret the values in these tables as absolutes. Think about why something shows up where it does in the spectrum. For example, the table values assume only one factor (e.g. a nearby halogen), but if multiple compounding factors exist (e.g. nearby halogen and aromatic ring), then the influence (downfield shift to higher ppm) may be greater (maybe 1ppm higher) than the table indicates. 2.   There are NO solvent, water, or other impurities displayed in these spectra. 3.   It may be difficult to distinguish every signal in the 13 C-NMR spectrum due to overlapping signals but it is still possible to assess the types of environments that exist. Further, the exact number of unique carbon signals (non-equivalent carbons) is provided above  each 13 C-NMR spectrum. 4.   If signals are labeled as “overlapped,” they are not equivalent; they are unique signals that occupy overlapping space in the spectrum. 5.   For all structures (including aromatic rings) assume no long range coupling/splitting effects (i.e. only consider coupling/splitting between protons that are 3 bonds away from each other). 6.   Remember, equivalent protons do not couple (split) with each other (even if they are separated by three  bonds). Protons are equivalent if they are in exactly equivalent electronic environments (i.e. they experience the rest of the molecule in exactly the same way). Note that it is possible to for protons attached to different carbon atoms to be equivalent. 7.   Remember that single bonds rotate, so symmetry can be disguised. Re-check PART 1 to be sure symmetry was not overlooked. 8.   The 1 H-NMR spectra will be labeled with the splitting patter. As you have seen, the designations are: s=singlet, d=doublet, t=triplet, q=quartet, m=multiplet (if a proton is split by two or more sets of non-equivalent protons, it will be termed multiplet for the simplification purpose of this assignment).     5 A) Using the information below, provide (i) the degrees of unsaturation and (ii) a single chemical structure that is consistent with all of the data on this page. Molecular Formula: C 4 H 10 O Mass Spectrum (mass of molecular ion: 74) (i) How many degrees of unsaturation exist in this molecule? !   1 H-NMR spectrum: 13 C-NMR spectrum (total of 2 unique signals in the 13 C-NMR spectrum): IR spectrum: (ii) In the space below, draw a single chemical structure that is consistent with the molecular formula, mass, 13 C and 1 H-NMR spectra, and IR spectrum above. If you draw more than one structure below, you must CIRCLE the answer you want to be graded. "# $% &# '%
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