"D.M. Procida" wrote in
message
...
Julian wrote:

Why am I left with a solid and a liquid, not just some dissolved
calcium
chloride?

If you leave it long enough you will get just liquid, the situation that
you
describe is because the liquid is saturated.

So, the crystals started absorbing moisuture, to the point of being
dissolved in the moisture they were absorbing.

As this happens, the stuff heats up (apparently this reaction produces a
lot of heat) and the water becomes super-saturated, and continues to
dissolve more of the crystals.

Then it starts cooling down, and as it cools down some of the calcium
chloride precipitates out of the water.

Is that correct?

Not really - far too complicated! The crystals absorb moisture until they
start to dissolve, the liquid thus produced is also hydroscopic and
continues to absorb water until the crystals have all dissolved. After that
the liquid still absorbs further moisture, but with reducing affectivity as
the concentration of calcium chloride reduces.

I was once given one of those 'throwaway' dehumidifier containers once. It
had a mark on the side about 1/2 way up, when the level reached the mark it
was time for a new one.

Julian.