Van Der Waals Forces

Question 1

Define Van der Waals forces.

2

Answer 1

Van der Waals forces are weak attractive forces between molecules resulting from the formation of temporary dipoles

They are the only forces of attraction between non-polar molecules

Question 2

Where do van der Waals forces exist?

Answer 2

They exist between molecules

Question 3

How do van der Waals forces exist?

Answer 3

They exist as a result of temporary internal shifts in the distribution of electrons within a molecule - temporary dipole

Question 4

What is a temporary dipole

Answer 4

Two poles with one sigma+ and the other sigma-

Question 5

For how long do van der Waals forces exist?

Answer 5

They exist only for an instant

Question 6

Why do van der Waals forces exist only for a second?

Answer 6

Because they are very weak

Question 7

Van der Waals forces are the only force of attraction between what?

Answer 7

They are the only forces of attraction that exist between noon-polar molecules

Question 8

Give one example of evidence for the existence of van der Waals forces.

Answer 8

The fact that gases that consist of non-polar molecules can be liquefied suggests there must be some attractive forces between the molecules

Question 9

What happens to van der Waals forces as the molecules get bigger?

Answer 9

The strength of the van der Waals forces increases

Question 10

Why does the strength of the van der Waals forces increase as the molecules get bigger?

Answer 10

This is because the increase in the number of electrons means bigger electron clouds, allowing the temporary dipoles to form more easily