[pop000]

How do I know which material:C3H8, SO3, F2
Has the highest molar mass and the highest Polarity

I think SO3 got the highest molar mass but I don't sure.

Hope you can help me :)

Thnaks

[Unknown008]

For the molar mass, what about find each molar mass?

The molar mass is obtained by adding the relative atomic mass of each atom present in the molecule.

The highest polarity is the molecule that contains a species which is often more negative than another. I don't know if you were taught the term 'electronegativity', but this is a way to determine whether a molecule is polar or not and deduce the relative strengths of these 'poles'.

If a molecule has one of the three most electronegative elements, it is already very likely to be polar.
Then, the molecule's centre of polarity must not coincide, that is the positive pole should not be in the same place as the negative pole, or else, they cancel out.
That's it, if those two conditions are met, you can say that the molecule has a high polarity!

[pop000]

Well OK but can you tell me form this list who got the most highest Polarity ?
Is need to be so3 or c3h8
But I don't sure.

I tell you I got Question like this Order the materials from the most high Force between particles to the most low

So I know that for material to be with high Force between particles he need to be with the most molar mass and highest Polarity
I got this list:KBr, F2, SO3, C3H8 I know that KBr have the most highest Polarity and molar mass

[Unknown008]

Okay, KBr indeed has the strongest forces between its particles but not because of its mass but because it is an ionic compound.

Molar mass has nothing to do with strength of intermolecular forces.

Then, you will have the polar molecules. However, all three molecules are non polar, all their centre of charge coincide.

So, how do you think you'll proceed now?

[pop000]

Yes but there is a difference between force between the molecular like:van der Waals force here the molar mass is very Important to know about the strong of the force.

And there force into the molecular like: Covalent bond.
So if they ask me about the force between the molecular so I need to see if there a van der Waals force or Hydrogen bond I see there is no Hydrogen bond but van der Waals force because there Polarity even Momentary Polarity like in F2

Do I Right?
Thnaks about your help.

[Unknown008]

Right! :)

You should consider only Van der Waals forces. And remember than momentary dipole are not due to atomic mass but are due to the number of electrons. The larger amount of electrons, the stronger the momentary dipole.

Since we are looking at the force between the particles, we don't consider the forces within the molecules, that is, we don't consider the intra-molecular covalent bonds.

[pop000]

Ok so from the list F2 SO3 C3H8 I can know that

SO3 have the most number of electrons. So "The larger amount of electrons, the stronger the momentary dipole".
then come C3H8 then F2 here I not sure 100%

so I answer like this:
the list:C3H8, SO3, F2 need to be like this from the most highest force between particles to the most low :1)SO2 2) C3H8 3)F2
because the force come stronger as there more number of electrons Since there is a higher probability of presence of polar moments of molecule.

tell me if this words is truth: "Mulary mass of material is a measure of the size of its electron cloud"?

[Unknown008]

The order is good :)

"Mulary mass of material is a measure of the size of its electron cloud"

Sorry, I don't understand the first word >.<

Could you make a little more effort about your English please?

[pop000]

Oh yea I will try to make my English better sorry about it.
I mean:Molar mass of material is a measure of the size of its electron cloud?

[Unknown008]

No, atomic mass is. Molar mass takes into account the number of neutrons as well, which doesn't affect Van der Waals forces.

[pop000]

Ok thanks so much about your time really help me.

[DrBob1]

This has been an interesting discourse.
The trigonal planar shape of SO3 makes it a nonpolar molecule, but the S-O bonds are very polar and so it has substantial dipole - dipole interactions. This is shown by the higher melting and boiling point of SO3 compared to the other two compounds. The molecular weight is often considered in discussions like this to show the role of the intermolecular interactions on the boiling point (the higher the M.W. the higher the expected boiling point) It would not seem pertinent here.