easy 10 points?

Question

CH3CH2OH and CH3OCH3 have different boiling points but the same composition, what attributes to this?

Answer 1

CH3CH2OH will have the higher boiling point. The two molecule have the same molar mass, so London dispersion forces are the same for both molecules. However, the alcohol has didpole-dipole forces and hydrogen bonds as additional forces. The ether (CH3OCH3) has only dipole-dipole forces in addition to the London dispersion forces. Hydrogen bonds are much stronger forces, so the alcohol has the higher boiling point

Answer 2

CH3CH2OH has hydrogen bonding, because there is a hydrogen attached to the oxygen atom In hydrogen bonding, the electron is more attracted to the oxygen, which is more electronegative. The oxygen becomes more negatively cahrged, the hydrogen more positive. This gives it greater attraction to the oxygen atom on an adjacent molecule. Because of this hydrogen bonding, more energy is required to break the intermolecular forces, therefore a higher boiling point results. In CH3OCH3 there is no hydrogen bonding, so the intermolecular forces are less, and the material boils away at a lower temperature.

Which is a danger... ethanol is a great compound to have around (especially in your beer) and much safer than dimethyl ether, which can create explosive clouds of vapor.

Answer 3

One thing that determines the boiling point of a substance is the extent to which the individual molecules are attracted to each other. Since boiling happens when molecules fly apart from each other, an increased attraction between molecules means you have to heat them up more to get them to boil.

Now the ethanol (CH3CH2OH) have a higher boiling point than the dimethyl ether (CH3OCH3). According to the above explanation, this indicates that the mutual attraction between the ethanol molecules is greater than that between the methyl ether molecules. Why is this?

The OH part of the ethanol can do something called "hydrogen bonding". This happens when the hydrogen atom is attracted to the extra electrons on the oxygen atom of another ethanol. So the OH parts of adjacent ethanols want to stay close together. Since they are attracted, they need more heat input to break them apart. The ether molecules can't do this hydrogen bonding, so they have less mutual attraction than ethanol, and boil at a lower temperature.

Answer 4

The location of the oxygen atom and therefore the functional group makes the difference. CH3CH2OH is ethanol which is alcohol and is very polar and should have the higher boiling point. CH3OCH3 is dimethyl ether and is non-polar and should also have a low boiling point.

Answer 5

Look at the molecular polarity or net polarity around the oxygens.

The electronegativities are C: 2.5, H: 2.1, O:3.0. Although the electronic geometry around oxygen is a slightly distorted tetrahedral and we're talking about alkyl groups rather than atoms, you can get away with simplying the picture thus:

Ethanol: C - O - H

Dimethyl ether: C - O - C

The ethanol has a more assymetrical dipole moment compared to DME (if the molecules were linear as (incorrectly) drawn, DME would a net dipole of zero). Therefore, it has a greater intermolecular forces of attraction (dipole-dipole) and higher boiling point.

jt

Answer 6

because the are bonded to different things? they are constitutional isomers? CH3CH2OH will have the higher boiling point. The two molecule have the same molar mass, so London dispersion forces are the same for both molecules. However, the alcohol has dipole-dipole forces and hydrogen bonds as additional forces. The ether (CH3OCH3) has only dipole-dipole forces in addition to the London dispersion forces. Hydrogen bonds are much stronger forces, so the alcohol has the higher boiling point. ?

Answer 7

Structural isomerism may also be more subtle, involving only a slight difference in the way the atoms are connected, rather than completely different molecules. An example of this is the difference between 1-propanol and 2-propanol (also known as isopropanol or rubbing alcohol). The only difference between these two molecules is the position at which the -OH (alcohol) group is attached. These two molecules are structural isomers.

Answer 8

The OH group causes hydrogen bonding between molecules. Stronger intermolecular forces give higher boiling points.

Answer 9

Well they are two different compounds! What would be a suprise would be f they had the same boiling point. Takes different amounts of energy to excite the molecules

Answer 10

Billy was a curios boy,
but Billy is no more,
cos what he though was H2O
was H2SO4

I know this doen't answer the question, but it's the only chemistry I remember from school, well that and the chemistry teacher almost blowing his own arm off with a stage powder flash bomb.