What factors affect the boiling point of polar molecules?

Click For Summary
SUMMARY

The boiling points of polar molecules are influenced by both molecular size and polarity, with hydrogen bonding being a significant factor. In the discussion, the correct arrangement of boiling points for methoxymethane, butane, pentane, and water is established as methoxymethane < butane < pentane < water. The weak dipole-dipole interactions in polar molecules like methoxymethane do not significantly affect boiling points compared to stronger hydrogen bonding present in water. Additionally, the comparison of carbon monoxide and nitrogen illustrates that polarity does not always correlate with boiling point.

PREREQUISITES
  • Understanding of molecular polarity and its effects on boiling points
  • Knowledge of hydrogen bonding and its role in phase changes
  • Familiarity with the properties of ethers and alkanes
  • Basic concepts of dielectric properties in polar molecules
NEXT STEPS
  • Research the impact of hydrogen bonding on boiling points in various compounds
  • Explore the relationship between molecular size and boiling point in alkanes and ethers
  • Investigate the dielectric properties of polar versus nonpolar molecules
  • Learn about phase change temperatures and their dependence on molecular interactions
USEFUL FOR

Chemistry students, researchers in molecular science, and professionals studying the physical properties of compounds will benefit from this discussion.

asdff529
Messages
38
Reaction score
0
arrange the boiling point of the following compounds
methoxymethane,butane,pentane and water
I quickly arrange like this
butane<pentane<methoxymethane<water
but after checking wiki,it should be
methoxymethane<butane<pentane<water
In my knowledge,methoxymethane is a polar molecule,so i should have a higher boiling point
Why,that it's not make sense?
Also which of the following has the higher priority when we are considering the boiling point, the polarization or the molecular size?
thanks!
 
Chemistry news on Phys.org
The ether is only slightly polar, so the hydrophobic interactions of the longer alkenes are stronger.
 
in general ethers can be regarded as basically nonpolar and have boiling points comparable to alkanes of similar molecular mass.

indeed have you noticed that the dipole-dipole interaction is extremely weak and doesn't really matter (in terms of phase change temperatures) in many cases, with only hydrogen bonding significantly altering the boiling point?

Carbon monoxide is isoelectronic with nitrogen N2, has the same mass, is much more polar than N2 yet they boil at almost the same temperature: 82 K vs. 78 K.

However, the dielectric properties of polar molecules are going to be different.
 

Similar threads

  • · Replies 6 ·
Replies
6
Views
4K
Replies
15
Views
3K
  • · Replies 3 ·
Replies
3
Views
7K
Replies
3
Views
3K
Replies
18
Views
8K
  • · Replies 5 ·
Replies
5
Views
6K
  • · Replies 6 ·
Replies
6
Views
4K
  • · Replies 4 ·
Replies
4
Views
4K
  • · Replies 2 ·
Replies
2
Views
28K
  • · Replies 2 ·
Replies
2
Views
7K