7A Intermolecular interactions

Question 1

how are London forces formed

Answer 1

molecule A and molecule B are both made of N2 as time passes on the electron density in one of the molecules became unsymmetrical this cause an instantaneous dipole in that molecule forming a delta positive and a delta negative charge. as molecule a is now charged in cause an induced dipole on the neighboring molecule as the positive delta would attract the pair of electrons in the other molecule making the electron density map unsymmetrical. this is a very rapid process

Question 2

are the formation of London forces from a non-polar molecule favorable?

Answer 2

yes they will always be aligned in a way where they would be fa

Question 3

what are the three features of London forces

Answer 3

1. as the number of electrons increases the stronger the londan force that is because the more electrons the greater the electron density fluctuation the larger the instantaneous dipole, meaning a larger boiling point
2. it depends on the size and shape of the molecule the more contact points there are the stronger the London force
3. it always forms between molecules whether a molecule has or doesn’t have a permanent dipole or a hydrogen bond

Question 4

intermolecular interations with perminat dipoles

Answer 4

if two molecules possess a permanent dipole they will also interact with one another as if there aligned correctly the two molecules interact with each other

Question 5

what is the problem with permanent dipoles

Answer 5

the random movement of molecules in something like a liquid would cause the dipoles to not always be aligned in the correct place and are their interactions wont be favorably causing them to repulse each other that’s why interactions between instantaneous and induced (London forces) dipoles are more significant between molecules

Question 6

what are the two interactions of permanent dipole

Answer 6

permanent dipole-permanent dipole

permanent dipole-induced dipole

Question 7

what is a hydrogen bond

Answer 7

intermolecular interaction (in which there is some evidence of bond formations) between the hydrogen atom of a molecule or a molecular fragment bonded to an atom which is more electronegative than hydrogen and another atom in the same or different molecule

Question 8

what is intramolecular hydrogen bonding

Answer 8

is a hydrogen atom bonded to an atom with the same molecule

Question 9

what is intermolecular hydrogen bonding

Answer 9

is a hydrogen atom bonded to an atom with a different molecule

Question 10

when is hydrogen bonding most significant

Answer 10

when hydrogen is bonded to very small very electronegative atoms such as oxygen, nitrogen and flourine

Question 11

al O-H groups form…

Answer 11

intermolecualr hydrogen bonds

Question 12

what is the interaction of water molecules forming a hydrogen bond

Answer 12

the negative delta cahrge of oxygen forms a hydrogen bond with a positively charged H in another water molecule, this isn’t only extreme dipole-dipole interactions it is also practical bond formation from the lone pair of oxygen and since it was two lone pairs it can be connected to two atoms

Question 13

what is evidence of a partial bond-forming in dipole-dipole interaction between water

Answer 13

a bond angle between the 3 atoms is 180 often like covalent bonds

Question 14

how to draw an interaction of water molecules forming a hydrogen bond

Answer 14

page 172

Question 15

all N-H groups form…

Answer 15

intermolecualr hydrogen bonds

Question 16

what is the only fluorine compound that forms hydrogen bonf\d

Answer 16

hydrogen fluoride