Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

15. Analytical Techniques:IR, NMR, Mass Spect

Mass Spect:Fragmentation

Organic Chemistry

15. Analytical Techniques:IR, NMR, Mass Spect

Mass Spect:Fragmentation

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Multiple Choice

A mass spectrum has an M and M + 2 peak in an ~ 3 : 1 ratio. Which atom is likely present in this molecule?

Sulfur

Chlorine

Oxygen

Bromine

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Verified step by step guidance

Understand the concept of isotopic abundance: Different elements have isotopes with varying natural abundances. This affects the mass spectrum peaks.

Identify the isotopes of chlorine: Chlorine has two main isotopes, Cl-35 and Cl-37. Cl-35 is more abundant, approximately 75%, while Cl-37 is about 25%. This results in a 3:1 ratio in the mass spectrum.

Compare the isotopic ratios: Sulfur, oxygen, and bromine have different isotopic distributions. For example, bromine has a 1:1 ratio due to Br-79 and Br-81 isotopes.

Analyze the mass spectrum peaks: The M peak corresponds to the most abundant isotope, while the M+2 peak corresponds to the less abundant isotope. A 3:1 ratio suggests the presence of chlorine.

Conclude based on isotopic evidence: Given the 3:1 ratio in the mass spectrum, chlorine is the most likely atom present in the molecule due to its isotopic distribution.