Van der waals forces can best be described as the attractive or repulsive forces that are formed between oppositely charged ions in a crystal. during dipole-dipole interactions between molecules. when molecules move apart in the absence of other forces. by a random, short-lived redistribution of electrons.

Correct by a random, short-lived redistribution of electrons.

van der Waal's forces are the weak intermolecular forces of attraction or repulsions that are seen in all molecules, when they come close to each other. These forces of attraction or repulsion are due to the momentary charges that develop between the electron clouds of one atom and the nuclei of the other atom. Therefore, the van der Waal's forces are due to the instantaneous dipoles that are produced between two atoms close to each other, due to the redistribution of electron clouds.

i know insulin is primary but i dont know the others im sorry

explanation:

"standard molar enthalpy:

h2o ( liquid water ) : - 285.8 kj/mole

h2o ( water vapor ) : - 241.8 kj / mole.

δhrxn = - 241. 8 - ( - 285.8 )= -241.8 + 285.8 = 44.0

answer: 44.0 kj"