[CNR-engineering]

Hey guys,

   I hate asking for help, but I have two question I just simply cant anwser, Ive read high and low and just cant seem to find any information. Any help is greatly appreciated, well here goes:

1.)  Predict which compound is an insulating ceramic material?
 MgZn2
 Li3P
 Li20
 LiCl
 GaAs

2.) What intermolecular force is the most responsible for the difference in boiling point between octane and pentane?
 Dispersion
 Dipole-Dipole interaction
 Dipole-induced dipole interaction
 Hydrogen bonding
 All of these

  If anyone could help me with these or direct me to a website or such to help me get some information on these subjects that would be great, Thanks and have a nice day.

[Arkcon]

1.)  Predict which compound is an insulating ceramic material?
 

Does the question truly not define whether it means thermal or electrical insulator?  Seems a bit unfair to you.

For number 2, can't you exclude at least some options given the structures of octane and pentane?

[CNR-engineering]

1. Im not sure I believe it means electrical ,but I guess there is no way of telling for sure.  Im really not sure were to begin with this question.

2.  Octane's chemical formula is  C8H18 , pentane's chemical formula is C5H12.  So I know its not hydrogen bonding, which eliminates all of these as a choice as well.  Im not sure if Im right ,  I know its not dipole induced dipole because they both contain hydrogen and carbon.  Both molecules I think are non-polar so that would eliminate dipole-dipole.  So im assuming its dispersion forces?

[Valdorod]

1)  Look for the material that is truly a ceramic, only one among your choices qualifies as a true ceramic.

2) Both of your compounds are non-polar covalent, only one of the choices is present strongly in non-polar covalent compounds.

Valdo