EXERCISE 5


A comet streaking through the solar system has a volume of
one cubic kilometer.  99% of its volume is water ice.  As it 
passes near the Sun, 0.1% of its volume is converted into water vapor.  

Water ice has a density of 0.92 gram per cubic centimeter.
Keeping in mind that 1 km = 100,000 cm, and that 1 kg = 1000 g,
about how many molecules of water are vaporized?  Remember
that a mole of water molecules has a total mass of 18 grams.