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Chemistry Forums for Students => High School Chemistry Forum => Topic started by: chopchop on March 17, 2004, 02:37:39 AM

Title: intermolecular forces
Post by: chopchop on March 17, 2004, 02:37:39 AM

Hi there
I got a few question that i not sure about and I hope someone  who is interest  in intermolecular forces is able to help me out please.

Question
Consider the molecules F2 and HCl
why should the strength of the intermolecular due to temporary dipoles be similar for these two molecules?

Intermolecular attraction due to permanent dipoles is more significant for (HCl/HBr)
Justify your choice

"                                               " temporary dipoles "                                    
"(HCl/HBr)
"                           "

 

Title: Re:intermolecular forces
Post by: Donaldson Tan on March 17, 2004, 02:54:00 AM

F2 has a total of 18e. HCl has a total of 18e too. Thus their molecular electron cloud should be of similar size, and thus exihibit similar strength of intermolecular temporary-dipole-temporary-dipole interaction.

Title: more question on intermolecular forces
Post by: chopchop on March 17, 2004, 11:17:19 PM

1) Intermolecular attraction due to permanent dipoles is more                                                    significant for (HCl/HBr)
Justify your choice

2)Intermolecular attraction due to temporary dipoles is more significant for (HCl/HBr)

Consider the boiling points of HCl and HBr in the above table on and your answer to 2(a) and 2(b).Circle the word  in the brackets that make the statement correct.

3)The attractive force that is more important in determining the relative boiling points of HCl and HBr is due to (temporary,permanent) dipoles. justify your choice.

thanx for your time

Title: Re:more question on intermolecular forces
Post by: Mitch on March 17, 2004, 11:56:51 PM

1) Whichever one has the largest difference in their electonegativities will contribute most to a permanent dipole.

Title: Re:more question on intermolecular forces
Post by: Donaldson Tan on March 19, 2004, 03:18:47 AM

1. HCl since Cl more electronegative than Br.

2. HBr more significant as it has more electrons.

3. permanent dipole, cuz the forces of attraction are much stronger.