The Student Room Group

Chemistry AS HELP!!!

Im really stuck on some topics that I just don't get mainly because my teacher goes over things too fast...
Can someone explain what the following things are
Van der walls forces
Dipoles?
Intermolecular forces
Hydrogen bonding and why is it important with water?
Why does water dissolve salt
What would happen if there was no hydrogen bonding in water?
Basically I don't really get any of these, I understand what intermolecular forces are as they are weak forces between molecules. But I am clueless about the others and I have searched but don't get the concept. Any help with these would be much appreciated :smile:
Reply 1
Avatar for 7253567
7253567
8
A dipole is caused when you have two different charges at either end if a molecule. This happens because you have two atoms with different levels of electro negativity (the ability to attract electrons) in a covalent bond.
Van der waal's forces are intermolecular forces. The occur when molecule has a dipole. The opposite charges means that the different molecules are attracted to each other.


Posted from TSR Mobile
Original post by Super199
Im really stuck on some topics that I just don't get mainly because my teacher goes over things too fast...
Can someone explain what the following things are
Van der walls forces
Dipoles?
Intermolecular forces
Hydrogen bonding and why is it important with water?
Why does water dissolve salt
What would happen if there was no hydrogen bonding in water?
Basically I don't really get any of these, I understand what intermolecular forces are as they are weak forces between molecules. But I am clueless about the others and I have searched but don't get the concept. Any help with these would be much appreciated :smile:



Intermolecular forces are any force of attraction between two molecules - e.g. water, or a fluorine molecule. It's almost like an umbrella term - hydrogen bonding and Van der Waals' forces are two examples

Hydrogen bonding is a special type of dipole-dipole interaction. It occurs when two molecules have a dipole
A dipole is when one atom in a molecule is more electronegative than another. It causes electrons to be more attracted to this more electronegative atom (it's Oxygen in hydrogen bonding), and that atom becomes slightly negatively charged. Due to electron deficiency in the hydrogen of the water, it becomes slightly positively charged.
So, when you have two molecules of water, the slightly negative oxygen attracts the slightly positive hydrogen on another molecule. This causes a weak bond between the two. Hydrogen bonds in mass (e.g. any considerable amount of water) are very strong. Hence why water has high surface tension.

Quick Reply

Related discussions

Latest

Trending

Trending

Articles for you