Structural isomer boiling points

In summary, the isomer C-C-C-N has a higher boiling point than CC(N)C due to larger contact area and stronger force of attraction. Hydrogen bonding involving N is only one factor, while other intermolecular forces also play a significant role.
  • #1
i_love_science
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Homework Statement
There are 4 different isomers of C3H9N. They have boiling points that range from 3°C to 48°C. Identify the isomers that you would expect to exhibit the lowest and highest boiling points. Explain your reasoning in terms of the intermolecular forces involved.
Relevant Equations
structural formulas
Why does the isomer C-C-C-N have the highest boiling point, rather than CC(N)C (where the N is attached to the second carbon)?
Isn't N able to form 3 H-bonds in both cases? Thanks.
 
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  • #2
What has larger contact area: two pencils, or two balls?
 
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  • #3
Larger contact area; more Force of attraction, so ...
 
  • #4
Physics guy said:
Larger contact area; more Force of attraction, so ...
Does the N in CC(N)C has less contact area because of the 3 C chain?
 
  • #5
i_love_science said:
Does the N in CC(N)C has less contact area because of the 3 C chain?
We are not talking bout the area of a single atom, it does not concern us here. We are trying to identify which of the isomers has larger area to have contact with another molecule. This will cause attraction due to wander walls force. Note that there are also other factors that come into play like Hydrogen bonding etc
 
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  • #6
Physics guy said:
We are not talking bout the area of a single atom, it does not concern us here. We are trying to identify which of the isomers has larger area to have contact with another molecule. This will cause attraction due to wander walls force. Note that there are also other factors that come into play like Hydrogen bonding etc
So the hydrogen bonding involving N is only one factor determining the force of attraction, other intermolecular forces play an major role as well?
Thanks, I understand now.
 

Related to Structural isomer boiling points

1. What is a structural isomer?

A structural isomer is a type of molecule that has the same chemical formula as another molecule, but a different arrangement of atoms. This results in different physical and chemical properties, such as boiling points.

2. How do structural isomers differ in boiling points?

Structural isomers have different boiling points because their different arrangements of atoms result in different intermolecular forces between molecules. These forces determine the amount of energy required to break the bonds and convert the substance from a liquid to a gas.

3. Do all structural isomers have different boiling points?

No, not all structural isomers have different boiling points. Some structural isomers have similar arrangements of atoms and therefore have similar intermolecular forces and boiling points. However, most structural isomers have different boiling points due to their unique arrangements of atoms.

4. How does branching affect the boiling point of structural isomers?

Branching in structural isomers can have a significant impact on boiling points. Generally, the more branching a molecule has, the lower its boiling point will be. This is because branching reduces the surface area of the molecule, which decreases the strength of intermolecular forces.

5. Can you predict the boiling point of a structural isomer?

It is difficult to predict the exact boiling point of a structural isomer without experimental data. However, in general, the boiling point of a structural isomer can be predicted by looking at its molecular structure and the types of intermolecular forces present. For example, molecules with stronger intermolecular forces, such as hydrogen bonding, tend to have higher boiling points.

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