Forces between molecules- van der Waals'

Question 1

how does the strength of intermolecular forces compare to ionic or covalent bonds?

Answer 1

weaker

Question 2

what are the three type of intermolecular force?

Answer 2

• van der Waals’
• permanent dipole-dipole
• hydrogen bonds

Question 3

in what type of particles are van der Waals’ forces the predominant force?

Answer 3

non-polar particles- those that do not have a permanent dipole moment

Question 4

what are some species that have an even electron distribution (van der Waals’ forces are predominant)?

Answer 4

• single atoms
• molecules of the same element
• hydrocarbons
• symmetrical molecules

Question 5

what are van der Waals’ forces caused by?

Answer 5

the attraction between temporary dipoles

Question 6

when is a temporary dipole formed?

Answer 6

when there is a momentary shift in electron density within the molecule’s electron cloud

Question 7

how do temporary dipoles affect neighbouring molecules?

Answer 7

cause a distortion in the charge cloud of neighbouring molecules- an induced temporary dipole

Question 8

how does the size of an atom or molecule affect induced dipole forces? why?

Answer 8

induced dipole forces (van der Waals’ forces) become stronger the larger the atom or molecule- because larger electron clouds are easier to deform

Question 9

boiling point in compounds held together by van der Waals’ forces? why?

Answer 9

low boiling point- forces are very weak and require little energy to break