(1) Which molecules exhibit only London (dispersion) forces? Br2
BF3 CH3Cl C2H6 NF3
(2) Which of the substances has polar interactions
(dipole–dipole forces) between molecules? CHF3 SO2 HBr N2 CCl4
(3) How much energy is required to melt 429 g of ice into liquid
water at 0 ∘C? The heat of fusion for water is 333.6 J/g.
(4) As an athlete exercises, sweat is produced and evaporated to
help maintain a proper body temperature. On average, an athlete
loses approximately 539 g of sweat during an hour of exercise. How
much energy is needed to evaporate the sweat that is produced? The
heat of vaporization for water is 2257 J/g.