Which statement about van der waals forces is true?
a)when the forces are weaker, a substance will have higher volatility.
b)when the forces are stronger, a substance will have lower viscosity.
c)when the forces are weaker, the boiling point of a substance will be higher.
d)when the forces are stronger, the melting point of a substance will be lower.

The two naturally occurring isotopes of chlorine are 35cl (34.969 amu, 75.77%) and 37cl (36.966 amu, 24.23%). the two naturally occurring isotopes of bromine are 79br (78.918 rm amu, 50.69%) and 81br (80.916 amu, 49.31%). chlorine and bromine combine to form bromine monochloride, brcl. 1. how many peaks will be present in a mass spectrum for brcl? the four combinations of molecule possible given these four isotopes are: 81br37cl, 81br35cl, 79br37cl, and 79br35cl. 2. what are the masses of the four different brcl molecules? express the masses using six significant figures, in decreasing numeric order (highest to lowest), separated by commas.