GChem help please!!

[osims]

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Hey guys, so im studying gchem right now and i cant seem to understand how you can tell the difference between a polar molecule and a non polar molecule. On the DAT they tend to ask questions like "which one is polar" from a list of compounds. can someone give me some examples? please help asap, thanks!!

 

[Hope2007]

Hey guys, so im studying gchem right now and i cant seem to understand how you can tell the difference between a polar molecule and a non polar molecule. On the DAT they tend to ask questions like "which one is polar" from a list of compounds. can someone give me some examples? please help asap, thanks!!

Is this a serious question???
Anyway, it's good to review:
(1) Non-polar bonding has an equal sharing of electrons
(2)Polar bonding has an unequal sharing of electrons. The number of shared electrons depends on the number of electrons needed to complete the octet
Also, tt depends on the electronegativity of an atom(s) in the molecule.
Ex) H2O is polar because Oxygen is an electronegative atom, therefore it tends to pull electrons towards itself (2), causing the molecule become polar.
while, CH4 is non-polar molecule because Carbon is a neutral atom and it equally shared the electrons to complete the octet rule (1)

 

[Montserrat]

I think you need to put the problems aside and re-read the text a bit, because this is pretty fundamental stuff. Going through practice problems without understanding the method of solution is going to be really inefficient.

 

[dentaldude8]

Read the examkrackers gchem book!

 

[osims]

what about the dipole-dipole moments? doesnt that factor in somewhere? and how do you know the direction of the dipole. its may be pretty fundamental stuff, but sometimes the easiest things are the hardest to understand for some people.

 

[gomawum]

I think those polar molecules has dipole moment (unequal sharing of electrons)

if more than two of the polar molecules are interacting those are dipole-dipole moment
(H-bond is strongest example of dipole diple moment)

non-polar can temporarly have dipole moment when it's in the neighbor of polar molecule and it's called Induced dipole

those induced dipole can cause another temporal dipole moment on neighboring non-polar molecule and it's called instantaneous dipole

those instant dipole-diple moment (b/t non-polar) is called London Force

correct me if I'm wrong

 

[raya23]

polar covalent bond is between atoms with small differences in electronegativity. nonpolar covalent is between atoms with same electronegativities. coordinate covalent is when a pair of bonding electrons come from just one of the atoms.

 

[raya23]

I think those polar molecules has dipole moment (unequal sharing of electrons)

if more than two of the polar molecules are interacting those are dipole-dipole moment
(H-bond is strongest example of dipole diple moment)

non-polar can temporarly have dipole moment when it's in the neighbor of polar molecule and it's called Induced dipole

those induced dipole can cause another temporal dipole moment on neighboring non-polar molecule and it's called instantaneous dipole

those instant dipole-diple moment (b/t non-polar) is called London Force

correct me if I'm wrong

h bonding and dipole dipole interactions are two out of three different intermolecular forces, where h bonding is the strongest, dipole dipole is in the middle, and dispersion is the weakest.