intermolecular forces

Question 1

what are induced dipole dipole interactions

Answer 1

• exist between all molecules
• movement of electrons produces an instantaneous dipole
  -instantaneous dipole induces a dipole on neighbouring molecule
  -act between induced dipole in diff molecules

Question 2

how does the strength of induced dipoles differ between molecules

Answer 2

the larger the molecule
- the larger the instantaneous and induced dipoles
- greater the induced dipole-dipole interactions
-stronger the attractive forces between molecules

Question 3

what are permanent dipole-dipole interactions

Answer 3

act between permanent dipoles in different polar molecules

Question 4

what is hydrogen bonding

Answer 4

-permanent dipole interaction between molecules containing :
-an electronegative atom with lone pairs
-a hydrogen atom attached to an electronegative atom
-between lone pair of an electronegative electron and hydrogen atom in a diff molecule
-strongest intermolecular force

Question 5

why is solid ice less dense than water

Answer 5

-hydrogen bonds hold water molecules apart in an open lattice structure
-water molecules in ice are further apart than in water
-solid ice less dense and so floats on water

Question 6

why does water have a relatively high melting point

Answer 6

-water has london and hydrogen bonding
- when lattice breaks the rigid arrangement of h bonds in ice is broken
- when water boils h bonds break completely