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

3. Acids and Bases

Organic Chemistry Reactions

Organic Chemistry

3. Acids and Bases

Organic Chemistry Reactions

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Multiple Choice

Which of the following is not a method used to determine the number of bacteria present in a sample?

Gas chromatography

Spectrophotometry

Flow cytometry

Colony counting on agar plates

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Verified step by step guidance

Understand the context: The problem is asking which method is not used for determining the number of bacteria in a sample. This involves understanding the typical methods used in microbiology for bacterial quantification.

Review each method: Begin by reviewing what each method entails. Gas chromatography is a technique used for separating and analyzing compounds that can be vaporized without decomposition.

Consider the application of each method: Spectrophotometry measures the amount of light that a sample absorbs, which can be used to estimate bacterial concentration by measuring the turbidity of a bacterial culture.

Flow cytometry is a technique that can count and analyze the size, shape, and properties of individual cells, including bacteria, as they flow in a fluid stream through a beam of light.

Colony counting on agar plates involves spreading a diluted sample on an agar plate and counting the number of colonies that grow, which directly indicates the number of viable bacteria in the sample.