A seed crystal was placed in a super-saturated solution. When crystals of solute formed, the resulting process was exothermic (felt warm). Why?

Evidently, this suggests that the crystals were releasing energy as they formed, once the seed crystal had been placed in the solution. However, why does crystal formation release energy?

1 Answer
Mar 26, 2017

Answer:

In general #"bond formation"# is #"exothermic"#, i.e. bond formation releases energy..............And certainly xtallization is an example of bond formation.

Explanation:

And this is an extension of the conservation of energy. To make that supersaturated solution, we probably had to heat the solution up to get all the solute into solution.......

The supersaturated solution is metastable, but with the introduction of the seed crystal, crystallization occurs........with the evolution of heat.

SO I suppose, the heat evolution is a consequence of the #"principle of conservation of energy"# (of course it is!).

#"Saturated solution" +"Solid" + Deltararr"Supersatured Solution"#

#"Supersaturated Solution"rarr"Solid" +"saturated solution"+Delta#

#"ENERGY is conserved."#