Chapter 16 Flashcards
Aldehyde
Alcohol
Ketone
Carboxylic Acid
Ester
Acids _ H+ Molecules.
Donate
Bases _ H+ Molecules.
Accept
Explain how to name Carboxylic Acids.
- Replace the parent alkane “e” with the prefix -oic acid
- When substituents are present, they are located by numbering starting at the COOH as carbon #1
- If the molecule contains 2 carboxylic acids we use the prefix -di in front of the -oic acid, keeping the “e” of the alkane name.
Benzoic Acid
What are the Physical Properties of Carboxylic Acids?
- They are highly polar compounds
- They have higher boiling points and is more soluble than alcohols, aldehydes, and ketones
- Smaller aliphatic carboxylic acids have sharp odors
What are the Chemical Properties of Carboxylic Acids?
They form strong hydrogen bonds
- In gas phase, the compound exists primarily as a dimer
- In liquid phase, many hydrogen bonds are formed to other acid molecules giving rise to aggregates of molecules.
- In aqueous solution, hydrogen bonds are formed with water molecules
Explain the Solubility of Carboxylic Acids?
Carboxylic acids…
- form hydrogen bonds with many water molecules.
- with one to five carbon atoms are very soluble in water.
- are less soluble as the number of carbons increases
Explain the Boiling Points of Carboxylic Acids.
The polar carboxyl groups allow carboxylic acids to form multiple hydrogen bonds with other carboxylic acid molecules.
This effect of hydrogen bonds gives carboxylic acids higher boiling points than alcohols, ketones, and aldehydes of similar molar mass.
Explain the Acidity of Carboxylic Acids.
- Carboxylic acids are weak acids.
- They dissociate in water to produce carboxylate ions and hydronium ions.
Explain Acid-Base Reactions of Carboxylic Acids.
Carboxylic acids DO react with strong bases to form carboxylate salts.
- A process of neutralization
- Acid protons are removed by the –OH to form H2O and carboxylate ion (more water soluble)
Esters are…
- Synthesized from the reaction of a carboxylic acid and alcohol.
- Found in fats and oils.
- Responsible for the aroma and flavor of bananas, oranges, and strawberries.
Esterification is…
- The reaction of a carboxylic acid and alcohol in the presence of an acid catalyst and heat to produce an ester.
- The replacement of the hydrogen atom in the carboxylic acid -OH group with an alkyl group from an alcohol.
Explain how to name Esters.
- The alkay group bonded to the oxygen is named first followed by the name of the acid.
- The suffix of the parent acid (-ic acid) is replaced with -ate.
Explain the Physical Properties of Esters.
- Because of the C=O group, esters can act as hydrogen bond acceptors.
- They are more soluble in water than the corresponding alkanes.
- Because they cannot form intermolecular hydrogen bonds between ester molecules, their boiling points are generally lower than corresponding alcohols.
Explain the Boiling Points of Esters.
Esters have…
- boiling points higher than those of alkanes and ethers.
- boiling points lower than those of alcohols and carboxylic acids of similar mass.
Because ester molecules do not have hydroxyl groups, they cannot hydrogen bond to each other.
Explain Acid Hydrolysis of Esters.
In acid hydrolysis…
- an ester reacts with water to produce a carboxylic acid and an alcohol.
- a water molecule provides an -OH group to convert the carbonyl group of the ester to a carboxyl group.
- an acid catalyst and heat are required.
Explain Base Hydrolysis of Esters.
Saponification or soap-making
Products are: Acid salt & Alcohol
- Acid can’t exist in basic conditions, so the product is the salt of the carboxylic acid using the cation of the base catalyst.
