Dipole-dipole in NH4+ ?

[sudo]

So, can someone please tell me if there are dipole-dipole interactions in a molecule of NH4+ ?

I know all the dipoles cancel out, so there would be a net dipole of 0, but does that mean that H-bonding is the only type of interaction in this molecule? Or is still correct to say that there are dipole-dipole interactions?

I hope that made sense...

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[Charles Darwin]

There would be induced dipoles (which are intermolecular forces) but the molecule itself is nonpolar (which is an intramolecular force).

Oh and SDN isn't for homework help.

 

[Aerus]

So, can someone please tell me if there are dipole-dipole interactions in a molecule of NH4+ ?

I know all the dipoles cancel out, so there would be a net dipole of 0, but does that mean that H-bonding is the only type of interaction in this molecule? Or is still correct to say that there are dipole-dipole interactions?

I hope that made sense...

If you're talking about the intramolecular forces, there IS a sort of "dipole-dipole".

What you're talking about when there is a net dipole of 0 is the INTERMOLECULAR forces. Since there is no net dipole, there is NO DIPOLE DIPOLE when examining the intermolecular forces.

But when examining its intramolecular forces within, there's a sort of dipole because the electronegativity of Nitrogen and Hydrogen are not the same.

Make sure you do not confuse your inter forces with intra forces.

 

[virtuoso735]

This should be in the MCAT Q&A questions forum.

 

[Aerus]

Oh and SDN isn't for homework help.

Also, this. 👍

SDN is more for advice on the premed route, not HW that pertains to the courses.

If you need extra chem help, try seeking a tutor, your professor, or a study group.

 

[ccrone]

So, can someone please tell me if there are dipole-dipole interactions in a molecule of NH4+ ?

I know all the dipoles cancel out, so there would be a net dipole of 0, but does that mean that H-bonding is the only type of interaction in this molecule? Or is still correct to say that there are dipole-dipole interactions?

I hope that made sense...

Few things...

First, this is an ion (not to be a jerk, but this is an important distinction, as it will form ionic bonds as opposed to covalent ones, as a general rule). Second, are you talking about INTRAmolecular forces, or INTERmolecular forces? There are no dipole-dipole interactions in a single molecule or ion. Dipole-dipole interactions occur between two molecules/ions where dipoles are involved.

Nitrogen is more electronegative than hydrogen, but if you draw out the structure of the ion, you will see that the nitrogen pulls equally from all four hydrogen atoms. As a result, adding the polarity vectors results in a sum of zero (ergo, no dipole moment). There are no dipole-dipole forces, nor is hydrogen bonding present (in a vast sea of NH4+ ions you have tons of h-bond donors, but no h-bond acceptors). The only intermolecular forces between NH4+ ions are van der waals (london dispersion forces). These intermolecular forces would hold the NH4+ ions together by virtue of the fact that the electrons in your ions can be anywhere in the ion at any given time (though the electron density will necessarily be concentrated around nitrogen). These differences in electron density create attractions between the NH4+ ions that allow these birds of a feather to "stick" together.

Hope that helps.

 

[theWUbear]

SDN isn't for homework help.

OP, I'd call the police. Charles Darwin is in your house, and he's ascertained that this question is for your homework.

 

[Charles Darwin]

OP, I'd call the police. Charles Darwin is in your house, and he's ascertained that this question is for your homework.

I didn't know bears were capable of critical thinking. And I was right.

 

[Aerus]

This could reasonably be construed as an MCAT topic and there's actually an MCAT Study Question Q & A forum just for questions like this (don't double post though, it's against the ToS). A mod will move this thread shortly.

I guess it could.

 

[theWUbear]

I thought bears weren't capable of critical thinking. And I was right.

I think this is what you meant to say. Work on that verbal before the MCAT, champ

 

[sector9]

Homework help threads are not allowed in pre-allo. Closing thread

If this is a question regarding MCAT preparation, then post your question in the MCAT Q&A forum.