The freezing point of water is 0° C. The Celsius (centigrade) scale is based off of water, with the freezing point at 0° and the boiling point at 100°. (Google will probably tell you this in 10 seconds, then you wouldn't have had to wait 7 hours!)
Cl2=3.17g/L
Ne=.901g/L
CO2=1.96g/l
therefore Cl2 is the densest gas under the given conditions.
Because of the sea waters density. If an object is less dense than the water it would not float
