[Ter]

Q: In ethanol, there are covalent bonds, hydrogen bonds and Van Der Waals. Which bonds or forces are broken when ethanol is vaporized?

I was thinking hydrogen bonds only since Van Der Waals will exist between vaporized ethanol too..is it right? But the VDW could be broken in the process of forming vapor and then VDW can then be formed between vapor particles again..is that right?

[fledarmus]

Typically, when you are talking about vapors, the assumption is that there are no forces holding the molecules together. If the molecules were being held together, they would condense and become either a liquid or solid.

Also, realize that van der waals forces are much weaker than hydrogen bonding. Even in vapor form, if two molecules are being held together, they are much more likely to be held together by hydrogen bonds than by van der waals forces.

The point the question is trying to make is that to vaporize a compound, you will remove the forces that hold two molecules together, but will not remove the forces that hold the atoms in a single molecule together.

[Ter]

So both hydrogen bonds and Van der waals will break?