Textbook Question
The liquids 1-butanol and butanal have similar molar masses. Which is expected to have the higher boiling point? Explain your choices.
Ch.15 Aldehydes and Ketones
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 15, Problem 63
Draw all the ketones you can with a chemical formula of C8H16O whose longest chain is eight carbons. Name each using both its IUPAC and common name.
Verified step by step guidance1
Step 1: Understand the structure of a ketone. A ketone is an organic compound where a carbonyl group (C=O) is bonded to two alkyl or aryl groups. The carbonyl group cannot be at the end of the chain, as that would make it an aldehyde.
Step 2: Analyze the molecular formula C₈H₁₆O. This indicates a saturated ketone (no double or triple bonds other than the carbonyl group) with eight carbons in total. The longest chain must include the carbonyl group and consist of eight carbons.
Step 3: Begin placing the carbonyl group at different positions along the eight-carbon chain. For example, the carbonyl group can be placed at carbon-2, carbon-3, or carbon-4 (placing it at carbon-5 would be equivalent to carbon-4 due to symmetry).
Step 4: Name each structure using IUPAC nomenclature. For example, if the carbonyl group is at carbon-2, the compound is named 2-octanone. If it is at carbon-3, the compound is named 3-octanone, and so on. For common names, identify the alkyl groups on either side of the carbonyl group and name the compound accordingly (e.g., methyl heptyl ketone for 2-octanone).
Step 5: Draw the structural formulas for each ketone. Ensure that the carbonyl group is correctly placed, and verify that the total number of carbons and hydrogens matches the molecular formula C₈H₁₆O. Label each structure with its IUPAC and common name.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Ketones
Ketones are organic compounds characterized by the presence of a carbonyl group (C=O) bonded to two carbon atoms. They are typically formed through the oxidation of secondary alcohols and are commonly found in various biological and industrial processes. In the context of the given formula C₈H₁₆O, ketones can be identified by ensuring that the carbonyl group is located within the carbon chain, not at the ends.
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Ketone Bodies Concept 1
IUPAC Naming
The International Union of Pure and Applied Chemistry (IUPAC) naming system provides a standardized method for naming chemical compounds. For ketones, the name is derived from the longest carbon chain containing the carbonyl group, with the suffix '-one' indicating the presence of the ketone functional group. The position of the carbonyl group is indicated by a number, which specifies its location within the carbon chain.
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Common Names
Common names are informal names used to identify chemical compounds, often based on historical or traditional usage rather than systematic rules. For ketones, common names may derive from the names of the alkyl groups attached to the carbonyl carbon. Understanding both IUPAC and common names is essential for accurately identifying and communicating about ketones in organic chemistry.
Related Practice
Textbook Question
Draw the structural formulas of the following compounds:
c. 2-Methoxy-2-methylpropane
Textbook Question
In Problem 15.24, you were given the structure of the free aldehyde form of glucose. Try to draw the two cyclic hemiacetal forms of glucose you would get if (a) the OH on C4 formed the ring and (b) the OH on C3 formed the ring.
Textbook Question
Many flavorings and perfumes are partially based on fragrant ketones, with far fewer being based on fragrant aldehydes. Why do you think ketones are used more frequently than aldehydes? See Section 15.5 for a clue.