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Water Study Questions
1. What is the structure of water, why is it a dipole and what does this allow water to do? H2O, oxygen has negative charge—Water is a dipole because of its geometry and difference in electronegativity between hydrogen and oxygen. Polar nature and geometry of water molecules allow them to form hydrogen bonds with each other and with dissolved hydrophilic substances.
2. What do the terms hydrophilic, hydrophobic, and amphiphilic mean and what do molecules described by theses terms possess?
Hydrophilic—water loving, able to form hydrogen bonds,
Hydrophobic—water hating, lack functional groups that allows the formation of hydrogen bonds, associate w/each other through hydrophobic interactions
Amphiphilic—both, polar head, non polar tail
3. How is a hydrogen bond different from a covalent bond?
Hydrogen bonds are weaker than covalent, but more H bonds makes stronger
4. What is a hydrophobic interaction and what make these interactions possible?
Hydrophobic interactions describe the relations between water and hydrophobes (low water-soluble molecules). Hydrophobes are nonpolar molecules and usually have a long chain of carbons that do not interact with water molecules. nonpolar substances like fat molecules tend to clump up together rather than distributing itself in a water medium, because this allow the fat molecules to have minimal contact with water.
5. What are hydrogen bond donors and acceptors? How do they differ?
Water forms hydrogen bonds with functional groups of organic molecules
Donor donates covalently bonded hydrogen to an electronegative acceptor atom
6. What does the pH of a solution refer to?
The amount of Hydrogen ions found in a solution.
7. Which pH values are considered acidic, basic and neutral?
1-6 acidic 7 neutral 8-14 basic
8. What does the pKa of an acid or base refer to?
Strength of acid
9. What is a buffer and at what pH value is a buffer most effective?
1. What is the structure of water, why is it a dipole and what does this allow water to do? H2O, oxygen has negative charge—Water is a dipole because of its geometry and difference in electronegativity between hydrogen and oxygen. Polar nature and geometry of water molecules allow them to form hydrogen bonds with each other and with dissolved hydrophilic substances.
2. What do the terms hydrophilic, hydrophobic, and amphiphilic mean and what do molecules described by theses terms possess?
Hydrophilic—water loving, able to form hydrogen bonds,
Hydrophobic—water hating, lack functional groups that allows the formation of hydrogen bonds, associate w/each other through hydrophobic interactions
Amphiphilic—both, polar head, non polar tail
3. How is a hydrogen bond different from a covalent bond?
Hydrogen bonds are weaker than covalent, but more H bonds makes stronger
4. What is a hydrophobic interaction and what make these interactions possible?
Hydrophobic interactions describe the relations between water and hydrophobes (low water-soluble molecules). Hydrophobes are nonpolar molecules and usually have a long chain of carbons that do not interact with water molecules. nonpolar substances like fat molecules tend to clump up together rather than distributing itself in a water medium, because this allow the fat molecules to have minimal contact with water.
5. What are hydrogen bond donors and acceptors? How do they differ?
Water forms hydrogen bonds with functional groups of organic molecules
Donor donates covalently bonded hydrogen to an electronegative acceptor atom
6. What does the pH of a solution refer to?
The amount of Hydrogen ions found in a solution.
7. Which pH values are considered acidic, basic and neutral?
1-6 acidic 7 neutral 8-14 basic
8. What does the pKa of an acid or base refer to?
Strength of acid
9. What is a buffer and at what pH value is a buffer most effective?