Concept explainers
(a)
Interpretation:
The curved arrow mechanism for the formation of the fragment from
Concept introduction:
In mass spectroscopy, compounds can be identified on the basis of the mass of the compound. When the compound breaks into fragment then they can be distinguished from the other compounds. This technique is also used to differentiate the isotopes of compounds. In amino acids, three types of fragments are observed in low energy collisions are a, b and y ions. It is known as tandem mass spectrometry.
(b)
Interpretation:
The curved arrow mechanism for the formation of the fragment from
Concept introduction:
In mass spectroscopy, compounds can be identified on the basis of the mass of the compound. When the compound breaks into fragment then they can be distinguished from the other compounds. This technique is also used to differentiate the isotopes of compounds. In amino acids, three types of fragments are observed in low energy collisions are a, b and y ions. It is known as tandem mass spectrometry.
(c)
Interpretation:
The curved arrow mechanism for the formation of the fragment from
Concept introduction:
In mass spectroscopy, compounds can be identified on the basis of the mass of the compound. When the compound breaks into fragment then they can be distinguished from the other compounds. This technique is also used to differentiate the isotopes of compounds. In amino acids, three types of fragments are observed in low energy collisions are a, b and y ions. It is known as tandem mass spectrometry.
Want to see the full answer?
Check out a sample textbook solutionChapter 27 Solutions
EBK ORGANIC CHEMISTRY
- 2. Explain the following: (a) How sites of variable activity in a heterogeneous catalyst might result in a polymer of high polydispersity. (b) Why molecular hydrogen is useful for controlling molecular weight in Ziegler-Natta polymerization. (c) Why only coordination catalysts are effective for polymerizing propylene and higher 1-alkenes.arrow_forward(a) (b) The quantum yield of fluorescence for anthracene is seen to be higher than that of biphenyl. Draw the two compounds and explain why this is so. The UV spectrum of isoquinoline has four 2 max values at 318, 305, 266 and 218 nm. Draw the compound and suggest what you would expect to happen if acid was added to solution and the spectrum is retaken.arrow_forward(c) How can the following be distinguished by UV-vis spectroscopy? (i) and (i) andarrow_forward
- (d) The compound (Z) exhibits an MS peak at m/z 93. Explain the fragmentation patterns : (Z)arrow_forwardi) Calculate the selectivity factor, , for the separation of the two enantiomers.(ii) Calculate the resolution, RS, of the pair of peaks corresponding to the two enantiomersof the medicine. (iii) Suggest two modifications that could be made to the analytical method describedabove with the aim of increasing the observed value of RS. Briefly explain your choicesand indicate any likely disadvantages of your proposed modifications. (iv) A non-racemic sample of the medicine gave peaks with retention times of 6.42 min(98.8% relative area) and 5.61 min (1.2% relative area). Calculate the enantiomericexcess of this second sample, stating any assumptions that you make.arrow_forward(a) A compound containing Mn, CO and Cl shows peaks at 1950 cm-¹-2000 cm -1 in IR spectrum. Mass spectral peaks were observed at =404, 376, 348, m Z 320, 292, 264, 236, 208, 180, 110, 55. Metastable peaks were observed at 349∙1, 322∙1, 294·3, 211, 183-3, 155-8, 67-2, 27.5. Suggest the most probable fragmentation pathway and predict the molecular structurearrow_forward
- 17.4 Give explanations for the following observations. (a) pK, values for CF;CO,H and CH3CO,H are 0.23 and 4.75, respectively. (b) The dipole moment of a gas phase NH3 molecule is 1.47 D, but that of NF3 is 0.24 D. (c) In electrophilic monosubstituted aryl compounds C,H4X, X = Me is activating and ortho- and para-directing, whereas X=CF; is deactivating and meta- directing. substitution reactions inarrow_forward3. (a) Clearly explain the three factors affecting chemical shifts (inductive effects, conjugation and magnetic anisotropy). (b) Clearly explain why acetylene, ethylene and benzene protons show their observed chemical shifts in 'H NMR. (c) Why do metal hydride protons exhibit such a high field chemical shift in the majority of the cases? when do you expect to see exceptions? (what type of metal complexes)arrow_forward(a) Describe in detail how you will determine the primary structure of protein. You have been given a mixture of lysine, histidine and cysteine. The isoelectric point of the amino acids are as follows: Histidine 7.64 Lysine 9.74 Cystenie 5.02 Show how you will separate the mixture into the pure forms. State and describe any instrument that you will use to separate the components in the mixture.arrow_forward
- (iii) State how the use of ¹¹B and ³¹P NMR spectroscopy can be used to confirm the formation of F3B-PD3. This answer requires that you construct labelled line diagrams to predict the NMR spectra in BF3, PD3 and F3B-PD3. (You may assume that the ¹¹B nucleus is 100% abundant as a first approximation). (iv) The molecule PD3 was substituted with one hydrogen to produce PD₂H. State how ¹H NMR spectroscopy can be used to confirm the formation of F3B PD₂H. This answer requires that you construct labelled line diagrams to predict the ¹H NMR spectra in the PD₂H and F3B-PD₂H. (You may assume that the 11B nucleus is 100% abundant as a first approximation).arrow_forward(c) Explain why glass cells are not used in, UV-spectroscopy.arrow_forwardGive a single benefit for each polymerisation from carrying them out under a nitrogen atmosphere? (d) Of the two polymers produced (A and B) one had Mn = 12,000 and a polydispersity of 1.1 and one a Mn = 11, 200 and a polydispersity of 1.7. Identify which set of molecular weight parameters corresponds to which polystyrene sample.arrow_forward
- ChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistryChemistryISBN:9781259911156Author:Raymond Chang Dr., Jason Overby ProfessorPublisher:McGraw-Hill EducationPrinciples of Instrumental AnalysisChemistryISBN:9781305577213Author:Douglas A. Skoog, F. James Holler, Stanley R. CrouchPublisher:Cengage Learning
- Organic ChemistryChemistryISBN:9780078021558Author:Janice Gorzynski Smith Dr.Publisher:McGraw-Hill EducationChemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningElementary Principles of Chemical Processes, Bind...ChemistryISBN:9781118431221Author:Richard M. Felder, Ronald W. Rousseau, Lisa G. BullardPublisher:WILEY