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Boiling point

Posted: Thu Dec 06, 2018 9:23 am
by sarahtang4B
Would NH3 have a lower boiling point compared to CH4 because NH3 has a lone pair of electrons?

Re: Boiling point

Posted: Thu Dec 06, 2018 9:28 am
by Courtney Quan 1C
Look at the intermolecular forces present: NH3 has the capacity to form hydrogen bonds because of its H-N bond. Hydrogen bonds, which are the strongest intermolecular forces, also have dipole-dipole and London forces (in descending order of strength of the intermolecular forces). CH4, on the other hand, only has London forces (which ALL molecules have) and is the weakest intermolecular force. As such, NH3 has a higher boiling point.

Re: Boiling point

Posted: Fri Dec 07, 2018 9:44 pm
by 305127455
Melting and boiling point depend on intermolecular forces. NH3 is polar with its two lone-pair electrons when CH4 is not. As a result, intermolecular forces between NH3 molecules are stronger.

Re: Boiling point

Posted: Sat Dec 08, 2018 12:17 am
by Chloe Likwong 2K
To sum up the previous comments, the stronger the bond, the higher the boiling point.

Re: Boiling point

Posted: Sat Dec 08, 2018 8:03 am
by Claudia Luong 4K
NH3 can have Hydrogen bonding (between H and N), dipole-dipole (due to NH3 being a polar molecule), and London dispersion forces. CH4 is nonpolar so it only has London dispersion forces. NH3 has more and also stronger intermolecular forces, so it will have a higher boiling point.

Re: Boiling point

Posted: Sat Dec 08, 2018 7:49 pm
by allisoncarr1i
Chloe Likwong 3K wrote:To sum up the previous comments, the stronger the bond, the higher the boiling point.

Is this due to the difficulty of breaking those bonds or for a different reason?