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26 Cards in this Set
- Front
- Back
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How are systematic names for carboxylic acids derived?
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By counting the # of carbons in the longest continuous chain that includes the carboxyl group & replacing the "-e" ending of the corresponding alkane by "-oic" acid.
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In naming, what outranks what, hydroxyl groups or carboxylic groups?
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Carboxylic groups outrank all the common groups
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Describe the structure of formic acid.
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Formic acid is planar, with one of its carbon-oxygen bonds shorter than the other, and with bond angles at carbon close to 120 degrees.
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What makes the carbonyl group of formic acid less electrophilic than that of a aldehyde or ketone?
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Lone-pair donation from the hydroxyl oxygen; this creates electron delocalization through resonance structures.
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How do the boiling points of carboxylic acids compare with the boiling points of hydrocarbons and oxygen-containing organic compounds of comparable size and shape? Explain.
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They are higher because of a unique hydrogen-bonding arrangement in which the hydroxyl group of one carboxylic acid acts as a proton donor toward the carbonyl oxygen of a second. In return, the hydroxyl proton of the second carboxylic acid interacts with the carbonyl oxygen of the first. As a result, the 2 carboxylic acid molecules are held together by TWO hydrogen bonds.
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How does the acidity of carboxylic acid compare to the acidity of water and alcohols?
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Carboxylic acids are the most acidic class of compounds that contain only carbon, hydrogen, and oxygen.
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Compare the ionization of ethanol to the ionization of acetic acid (acid strength).
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When ethanol ionizes (using water), it forms an ethoxide ion in which the negative charge on the oxygen is stabilized mainly by solvation. When acetic acid ionizes, the acetate ion that is formed is stabilized by solvation AND the inductive effect of the carbonyl group and the resonance effect of the carbonyl group. Thus, the pka of the ionization of ethanol is 16, and the pka of the ionization of acetic acid is 4.6
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What happens to carboxylic acids in the presence of strong bases?
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They are neutralized rapidly and quantitatively.
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How are the salts formed on neutralization of carboxylic acids named?
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By first specifying the metal ion, and then adding the name of the acid modified by replacing "-ic acid" by " -ate"
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Describe the solubility behavior of salts of carboxylic acids containing 12-18 carbons.
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They are amphiphilic; the carboxylate group is hydrophilic, while the long hydrocarbon chain are lipophilic (fat-loving). When one of these molecules is placed in water, the hydrophilic carboxylate group encourages the formation of a solution while the lipophilic alkyl chain discouarges it.
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What happens when salts of carboxylic acids are placed in water. Describe.
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Micelles are formed. A micelle is composed of 50-100 individual molecules, with the polar carboxylate groups directed toward its outside where they experience attractive forces with water and sodium ions, while the nonpolar hydrocarbon chains are directed toward the interior of the micelle where individually weak but cumulatively significant induced-diple/induced-dipole forces bind them together.
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What happens when two micelles are placed together? Why?
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They repel each other because their surfaces are negatively charged.
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What is an example of a common carboxylic acid salt?
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Sodium stearate.
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How are systematic names for carboxylic acids derived?
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By counting the # of carbons in the longest continuous chain that includes the carboxyl group & replacing the "-e" ending of the corresponding alkane by "-oic" acid.
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In naming, what outranks what, hydroxyl groups or carboxylic groups?
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Carboxylic groups outrank all the common groups
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Describe the structure of formic acid.
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Formic acid is planar, with one of its carbon-oxygen bonds shorter than the other, and with bond angles at carbon close to 120 degrees.
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What makes the carbonyl group of formic acid less electrophilic than that of a aldehyde or ketone?
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Lone-pair donation from the hydroxyl oxygen; this creates electron delocalization through resonance structures.
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How do the boiling points of carboxylic acids compare with the boiling points of hydrocarbons and oxygen-containing organic compounds of comparable size and shape? Explain.
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They are higher because of a unique hydrogen-bonding arrangement in which the hydroxyl group of one carboxylic acid acts as a proton donor toward the carbonyl oxygen of a second. In return, the hydroxyl proton of the second carboxylic acid interacts with the carbonyl oxygen of the first. As a result, the 2 carboxylic acid molecules are held together by TWO hydrogen bonds.
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How does the acidity of carboxylic acid compare to the acidity of water and alcohols?
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Carboxylic acids are the most acidic class of compounds that contain only carbon, hydrogen, and oxygen.
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Compare the ionization of ethanol to the ionization of acetic acid (acid strength).
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When ethanol ionizes (using water), it forms an ethoxide ion in which the negative charge on the oxygen is stabilized mainly by solvation. When acetic acid ionizes, the acetate ion that is formed is stabilized by solvation AND the inductive effect of the carbonyl group and the resonance effect of the carbonyl group. Thus, the pka of the ionization of ethanol is 16, and the pka of the ionization of acetic acid is 4.6
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What happens to carboxylic acids in the presence of strong bases?
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They are neutralized rapidly and quantitatively.
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How are the salts formed on neutralization of carboxylic acids named?
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By first specifying the metal ion, and then adding the name of the acid modified by replacing "-ic acid" by " -ate"
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Describe the solubility behavior of salts of carboxylic acids containing 12-18 carbons.
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They are amphiphilic; the carboxylate group is hydrophilic, while the long hydrocarbon chain are lipophilic (fat-loving). When one of these molecules is placed in water, the hydrophilic carboxylate group encourages the formation of a solution while the lipophilic alkyl chain discouarges it.
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What happens when salts of carboxylic acids are placed in water. Describe.
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Micelles are formed. A micelle is composed of 50-100 individual molecules, with the polar carboxylate groups directed toward its outside where they experience attractive forces with water and sodium ions, while the nonpolar hydrocarbon chains are directed toward the interior of the micelle where individually weak but cumulatively significant induced-diple/induced-dipole forces bind them together.
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What happens when two micelles are placed together? Why?
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They repel each other because their surfaces are negatively charged.
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What is an example of a common carboxylic acid salt?
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Sodium stearate.
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