Ch 14: Alcohols, Ethers, Thiols and Chiral Molecules

What types of bonds do organic compounds contain?

Carbon-carbon (C–C) and carbon-hydrogen (C–H) bonds

In organic chemistry notation, what does the capital letter R represent?

The carbon backbone/chain of an organic molecule

Alcohols are organic molecules that contain a…

Hydroxyl group (OH)

What determines the properties and reactions of alcohols?

The hydroxyl group (–OH)

What is the geometry/shape of the carbon bonded to the hydroxyl group in alcohols? What is the bond angle?

Tetrahedral, 109.5º

Are alcohols polar or nonpolar?

Polar

Which bonds in the hydroxyl group in alcohols are polar?

The C-O bond and the O-H bond

How are alcohols classified?

As primary (1°), secondary (2°), or tertiary (3°)

How can we classify whether an alcohol is primary, secondary, or tertiary?

The number of carbon atoms attached to the carbon with the –OH group

What is a primary (1°) alcohol?

An alcohol where the carbon with –OH is bonded to one other carbon

What is a secondary (2°) alcohol?

An alcohol where the carbon with –OH is bonded to two other carbons

What is a tertiary (3°) alcohol?

An alcohol where the carbon with –OH is bonded to three other carbons

Alcohols have partial charges because the O in the hydroxyl group is slightly ________ and the H is slightly _______, making alcohols polar.

negative; positive

Alcohols are polar because their…

Hydroxyl group (-OH) is polar

What type of intermolecular force is most prominent between alcohol molecules?

Hydrogen bonding 

Alcohols form hydrogen bonds because…

Because of the partial charges between the O and H in their hydroxyl group

What are boiling points?

The temperature where a liquid becomes a gas

The boiling point of a molecule is when the molecule gains enough ________ to escape into vapor:

Energy

Stronger molecular forces = __________ boiling points:

Higher

Weaker molecular forces = __________ boiling points:

Lower

Stronger molecular forces have _______ boiling points because the molecules are held together tighter

It takes more energy to pull them apart, so the liquid needs to be ______ to boil. 

Higher; Hotter

The _______ hydrogen bonds between alcohol molecules makes it more difficult for the liquid alcohol molecules to escape to the vapor phase, which is why alcohol boiling points are much _______:

Strong; Higher

Why do alcohols have higher boiling points than expected?

Because hydrogen bonding between alcohol molecules requires more energy to break

If molecules containing the following functional group were all isomers which would have the highest boiling point?

Ether, Ketone, Alcohol, Aldehyde:

Alcohol

Can alcohols form hydrogen bonds with water molecules?

Yes

Can alcohols form hydrogen bonds with themselves?

Yes

Alcohols have a polar hydroxyl group (OH) that is capable of hydrogen bonding making them ________ in water:

Soluble 

How does the size of the hydrocarbon chain affect alcohol solubility?

The larger the nonpolar chain, the less soluble the alcohol becomes in water.

How many carbons make an alcohol generally soluble in water?

Fewer than five carbons

Are alcohols soluble in water?

Yes, but it depends on how large the molecule is

How many carbons make an alcohol generally insoluble in water?

More than five carbons 

Are smaller alcohols soluble or insoluble in water?

Soluble

Are larger alcohols soluble or insoluble in water?

Insoluble

How can you determine whether an alcohol/molecule is soluble or insoluble in water?

By counting how many carbons it has (1-4 soluble, 5 or more insolule)

The longer the carbon chain, the more ________ the molecule becomes, which reduces solubility in water.

Nonpolar

What is the general structure of an alcohol?

R-O-H

What is hydrogen bonding?

When one molecule’s hydrogen (attached to an O,N, or F) is drawn to another molecule’s O,N, or F

What kind of bonds do molecules need to have in order to bond with each other via hydrogen bonding?

an OH, NH, or HF bond

If a molecule does not have an OH, NH, or HF group, they can’t form hydrogen bonds with each other, but might still bond with other molecules that do such as…

Water

What makes up an Ether?

An oxygen atom bonded to two carbon groups

What is the general formula of an Ether?

R-O-R or R-O-R’ (if the carbon groups are different)

Are Ethers polar?

Yes ethers are slightly polar because of the C-O bonds 

What is a cyclic Ether?

An ether in the shape of a ring 

Can ethers form hydrogen bonds with themselves?

No (they don’t have an O-H bond)

Ethers have ________ intermolecular forces than alcohols:

Weaker 

Ethers have ________ boiling points than alcohols:

Lower

What can Ethers form hydrogen bonds with?

Water

Are Ethers soluble in water?

Yes- Small ethers are soluble in water (large ethers are insoluble)

What atom replaces oxygen in thiols and thioethers?

Sulfur

What is the general formula of a thiol?

R-S-H

What two organic compounds contain sulfur instead of oxygen?

Thiols and thioethers 

What is the general formula of thioethers?

R-S-R or R-S-R’

Can thiols and thioethers form hydrogen bonds with themselves?

No

How do thiols’ intermolecular forces compare to alcohols?

Thiols have weaker intermolecular forces than alcohols

How do the melting and boiling points of thiols compare to alcohols?

Thiols have lower melting and boiling points than alcohols

What are thiols known for?

Their strong odor

Are thiols and thioethers polar or nonpolar?

Slightly polar

Can thiols and thioethers for hydrogen bonds with water?

Yes- it can weakly bond with water (much weaker than alcohols)

Are thiols and thioethers soluble in water?

yes they are slightly soluble (not nearly as much as alcohols)

What are the two main reactions of alcohols?

Dehydration and oxidation

What happens during the dehydration reaction of alcohols?

The alcohol loses a water molecule and produces alkenes

What is the product of a dehydration reaction of alcohols?

An alkene + H2O (water)

What is the general formula of an alkene?

C double bond C

What bond change occurs in alcohol oxidation to produce carbonyl groups?

A C-H bond is replaced with A C=O bond

An aldehyde is composed of a carbonyl group at the end of a carbon chain bonded to…

At least 1 hydrogen atom

A ketone is composed of a carbonyl group bonded to…

Two carbon groups (R and R)

A carboxylic acid is composed of a carbonyl group bonded to a…

Hydroxyl group (OH)

Oxidation is when ______ is removed or _______ atoms are added:

Hydrogen; oxygen

Oxidation results in the formation of ________-containing compounds:

Carbonyl

In an oxidation reaction of alcohols, a primary alcohol 1º > ___________ > ___________:

Aldehyde > Carboxylic Acid

In an oxidation reaction of alcohols, a secondary alcohol 2º > ___________

Ketone

Do tertiary alcohols undergo oxidation?

No- they have no reaction

What do oxidation reactions of thiols produce?

Disulfides (compounds that contain a sulfur-sulfur bond)

If two objects cannot be aligned no matter how you rotate or flip them they are…

(don’t perfectly match)

Chiral (cannot be superimposed)

If two objects can be perfectly aligned when rotated or flipped they are…

Achiral (can be superimposed)

If a carbon atom has four different groups attached (chiral center), what does this mean about the molecules chirality?

It is Chiral

If a molecule has duplicate groups/ two or more identical groups, what does this mean about the molecules chirality?

It is achiral

What does this symbol [o] mean?

Oxidation

What does this symbol [R] Mean?

Reduction

If a molecule has at least 1 carbon atom with 4 different groups, is it chiral or achiral?

Chiral 

If a molecule has no carbon with 4 different groups, is it chiral or achiral?

Achiral

If a molecule has a carbon with two or more identical groups, is it chiral or achiral?

Achiral

What are chiral carbons?

Carbons bonded to 4 different groups

If a molecule has double or triple bonds, is it achiral or chiral?

Achiral 

If a molecule is gaining oxygen is it undergoing oxidation or reduction?

Oxidation

If a molecule is losing oxygen is it undergoing oxidation or reduction?

Reduction

If a molecule is gaining hydrogen is it undergoing oxidation or reduction?

Reduction

If a molecule is losing hydrogen is it undergoing oxidation or reduction?

Oxidation

When being asked to determine if a molecule is going through oxidation or reduction, What are the 2 parts of the molecule you should look at?

The reactant (what you start with) and the product (what you end with)

What is the product of the oxidation of an alcohol?

A carbonyl compound

What is the product of the reduction of an aldehyde?

A primary alcohol

What is the product of the reduction of a Ketone?

A secondary alcohol

What is the product of the reduction of a carboxylic acid?

A primary alcohol