91Ó°ÊÓ

Does the strength of the intermolecular forces in a liquid change as the liquid is heated? Explain. Why does liquid viscosity decrease with rising temperature?

Which forces are intramolecular and which intermolecular?

(a) Those allowing fog to form on a cool, humid evening

(b) Those allowing water to form when ${\mathbf{H}}_{\mathbf{2}}$is sparked

(c) Those allowing liquid benzene to crystallize when cooled

(d) Those responsible for the low boiling point of hexane

What is the number of atoms per unit cell for each metal?

(a) Polonium, Po (b) Manganese, Mn (c) Silver, Ag