Textbook Question
Predict which member of each group is most soluble in water, and explain the reasons for your predictions.
b. chlorocyclohexane, cyclohexanol, or cyclohexane-1,2-diol
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2. Molecular Representations
How To Determine Solubility
2:48 minutesProblem 9d
Textbook Question
Classify the following molecules as hydrophilic, hydrophobic, lipophilic, or lipophobic. Each molecule should have two classifications.
(d) 
Verified step by step guidance1
Step 1: Begin by understanding the definitions of the terms hydrophilic, hydrophobic, lipophilic, and lipophobic. Hydrophilic refers to molecules that interact well with water (water-loving), while hydrophobic refers to molecules that repel water (water-fearing). Lipophilic refers to molecules that dissolve well in lipids or fats (fat-loving), and lipophobic refers to molecules that repel lipids or fats (fat-fearing).
Step 2: Examine the structure of the molecule provided in part (d). Look for functional groups or structural features that indicate polarity or non-polarity. Polar groups, such as hydroxyl (-OH), carboxyl (-COOH), or amino (-NH2), tend to make a molecule hydrophilic and lipophobic. Non-polar groups, such as alkyl chains or aromatic rings, tend to make a molecule hydrophobic and lipophilic.
Step 3: Determine the molecule's solubility in water and lipids based on its structure. If the molecule has a high proportion of polar groups, it is likely hydrophilic and lipophobic. If the molecule has a high proportion of non-polar groups, it is likely hydrophobic and lipophilic.
Step 4: Consider the balance between polar and non-polar regions in the molecule. Some molecules may have both hydrophilic and lipophilic properties due to the presence of both polar and non-polar regions. For example, amphiphilic molecules, such as phospholipids, have a hydrophilic head and a lipophilic tail.
Step 5: Assign the two classifications for the molecule based on the analysis above. Ensure that the classifications are consistent with the molecule's structural features and solubility properties.
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Video duration:
2mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Hydrophilicity and Hydrophobicity
Hydrophilicity refers to the affinity of a molecule for water, often due to the presence of polar functional groups that can form hydrogen bonds with water. Conversely, hydrophobicity describes the tendency of nonpolar molecules to repel water, making them insoluble in aqueous environments. Understanding these properties is crucial for predicting how molecules interact in biological systems.
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Lipophilicity and Lipophobicity
Lipophilicity indicates a molecule's affinity for lipids or fats, often associated with nonpolar characteristics that allow for solubility in organic solvents. In contrast, lipophobicity describes molecules that do not interact favorably with lipids, typically due to polar or charged groups. These classifications are essential for understanding the behavior of molecules in biological membranes and drug design.
Functional Groups and Molecular Classification
Functional groups are specific groups of atoms within molecules that determine their chemical reactivity and properties. The presence of certain functional groups, such as hydroxyl (-OH) or carboxyl (-COOH), can influence whether a molecule is classified as hydrophilic or hydrophobic, and similarly for lipophilic or lipophobic. Recognizing these groups is vital for accurately classifying and predicting the behavior of organic molecules.
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