Question

Order Ar, Si, and CCl4 in order of increasing boiling point

Answer 1

I have looked up the actual boiling points online and it appears the order should be Ar, CCl4,Si. Why does silicon have such a high boiling point? I understand that Ar is lowest because it is a noble gas and is a gas usually, but I figured past that I would just compare molecular mass. The greater the mass, the greater the intermolecular forces and the subsequent increase in boiling point. But silicon is less massive than carbon tetrachloride. Am i missing something?

Answer 2

less energy to break the bonds on carbon tet.

Answer 3

Really? why is that?

Answer 4

I know that carbon tet. is non-polar so it only has Disperson Forces, but isn't Silicon by its self nonpolar as well?

Answer 5

boiling point is dependant on intermolecular forces of attraction AND molar maass.

Answer 6

Yes well carbon tet has a greater mass and wouldn't they both only have London dispersion forces, because neither would have hydrogen bonds, ion dipole bonds, or dipole dipole bonds

Answer 7

Assuming that they're talking about solid silicon, it's framework exists in a network of silicon atoms just like the tetrahedral arrangement, much like that or solid carbon (diamond). I'm going to argue that the Si bond is stronger which is what makes it higher boiling.

Answer 8

Oh that does make sense. It is so tightly packed in a crystalline structure that is hard to overcome. Thanks!