[1] When a mixture of pure water and pure-water ice in a beaker is progressively frozen the temperature stays constant until all the water is frozen, while when a mixture of seawater and ice in a beaker is progressively frozen the temperature becomes colder and colder. Why is this?

[2] A small body of seawater is isolated from the ocean (perhaps by a growing sandbar in front of a lagoon). It is on average 5 m deep, and has a salinity of 35.00‰. It is winter and now the surface freezes; the ice thickness is 537.14 cm thick. What is the temperature of the bottom water in this lagoon? The density of ice is 0.9167 g mL–1.

[3] The worldwide rise in sea level is about 3 mm per year. Suppose this was all from melting ice, what volume of ice would have to melt each year to cause this rise?

[4] What is the salinity above which a vertically well-mixed body of water must cool all the way to the bottom before it can begin to freeze?

[5] In Table 2.2 there is the statement that 1 kg of seawater contains about 3.225 Ô 1025 molecules of water. Show how this was calculated.

[6] A sample of water is known to have an absolute ratio D/H = 120 Ô 10-6. What is the dD of this sample? Where does it seem likely that it could have come from (assuming somewhere in nature)?