Boiling point

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Kaitlynn Tran 3F
Posts: 54
Joined: Wed Sep 18, 2019 12:20 am

Boiling point

Postby Kaitlynn Tran 3F » Sat Dec 07, 2019 12:26 pm

So I know that the relative strengths for bonds are ionic > hydrogen > dipole-dipole > london dispersion, and as the bonds get stronger, the boiling point gets higher due to more energy required to break the bond. However, factors such as molecular size and surface area are factors that increase boiling point as well.

When comparing two molecules such as NH3 and PH3, which would have a higher boiling point? NH3 has hydrogen bonding, but PH3 has a larger molecular size, so I don't know how to rank them.

Midori Hupfeld 3D
Posts: 55
Joined: Fri Aug 30, 2019 12:17 am

Re: Boiling point

Postby Midori Hupfeld 3D » Sat Dec 07, 2019 12:28 pm

First, remember to say the strengths of the intermolecular forces between compounds, because it is not the actual intramolecular bonds. Also, NH3 has the greater boiling point, because it actually has hydrogen bonding (remember that you can form hydrogen bonds only on Hydrogens that are bonded to N, O, or F).

Kaitlynn Tran 3F
Posts: 54
Joined: Wed Sep 18, 2019 12:20 am

Re: Boiling point

Postby Kaitlynn Tran 3F » Sat Dec 07, 2019 12:30 pm

Midori Hupfeld 3D wrote:First, remember to say the strengths of the intermolecular forces between compounds, because it is not the actual intramolecular bonds. Also, NH3 has the greater boiling point, because it actually has hydrogen bonding (remember that you can form hydrogen bonds only on Hydrogens that are bonded to N, O, or F).


So hydrogen bonding would result in a higher boiling point than having a larger molecular size would?

Charysa Santos 4G
Posts: 107
Joined: Wed Sep 18, 2019 12:21 am

Re: Boiling point

Postby Charysa Santos 4G » Sat Dec 07, 2019 12:34 pm

Yes, hydrogen bonding would result in a higher boiling point because compared to the PH3, Nitrogen has far greater electronegativity, which means that it is able to form much stronger (hydrogen) bonds which require more energy to break (as in boiling).

Nan_Guan_3J
Posts: 36
Joined: Wed Sep 30, 2020 9:59 pm

Re: Boiling point

Postby Nan_Guan_3J » Sat Oct 17, 2020 7:02 am

NH3 can be considered as a special case because it has hydrogen bond which is relatively strong. NH3 and PH3 have similar molar mass.


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