If not when does this occur through dissolving salts and why?Molecular Manipulations - 23-5-2015 at 19:54
I'll let you look up the 'if' but I'll explain the 'why or why not'.
If a salt dissolves exothermically that means the solvant-solute van der Waals force (polar water's attraction to the polar ions) is stronger than the
solute-solute van der Waals force (the crystal's lattice, or the polar ions attraction to each other). If it dissolves endothermically then the
solute-solute force is stronger. Amos - 24-5-2015 at 08:27
This sounds like a question off a chemistry worksheet rather than scientific inquiry... blogfast25 - 24-5-2015 at 08:43
If not when does this occur through dissolving salts and why?
Dissolving salts is two processes.
1) Breaking all the ionic bonds in the lattice. That's known as the Lattice Energy.
2) Solvation: interaction between the solute's ions and the solvent's molecules releases energy.
Which of both is the largest determines whether the dissolution is exothermic or endothermic.
Dissolution also ALWAYS increases Entropy (probability) of the system. That's why Endothermic dissolutions can still proceed: ΔG = ΔH - TΔS, as
long as - TΔS is more negative than ΔH, ΔG < 0 and the dissolution is thermodynamically favourable.Yttrium2 - 24-5-2015 at 09:41
I don't think I quite learned about this in Gen Chem 1, hopefully it is in Gen chem2
