[s0610038]

How cold packs actually works?
And what kind of situation should we use ice pack in stead of heat pack?

Ammonium nitrate in water
Potassium nitrate in water
Sodium chloride in water
Calcium chloride in water

I know these compounds are commonly used for a cold pack, but which is the best? May I know the delta H of all of those elements dissolved in water? (kJ/mol)

I know i am annoying but please, i beg for some help... Thanks so much..
Thanks for helping

[Professor 0110]

Would this website help you at all? http://www.sciencebuddies.org/science-fair-projects/project_ideas/Chem_p081.shtml

It describes the thermodynamics and chemistry of cold packs using ammonium nitrate.

Have fun.

[s0610038]

Yes that website is really helpful~!

but how can I obtain the delta H of the compounds dissolved in H2O?
Thanks for helping =]