Self-Heating Drinks: What's the Chemical Reaction?

[noagname]

I went to walmart and found these self heating drinks/soups. All you have to do is twist a knob and wait a couple minutes and its ready. After looking online i wasn't able to get a straight answer. Is there a difference between the warming chemicals in the soups vs. hand warmers.

I'm looking for information on what they use in those drinks, as well as other chemical reactions to release heat to heat something small like a drink. Are there more potent combinations that are still safe for people to use in things like the self heating drinks?

 

[mgb_phys]

The handwarmers use powdered iron which oxidises when exposed to air giving off heat - it is intended to be fairly slow and low power, to give a small amount of heat for hours.
The cup heaters use anhydrous calcium chloride and water to give a lot of heat fairly quickly.

see http://www.stress.com/consumertier3.php?pid=307

 

[noagname]

so what makes some stronger than others

 

[mgb_phys]

The mass of reactants present controls the total amount of heat.
You could control the speed of heating be either allowing the water in gradually, possible with some pourous membrane or by the particle size of the salt.
The final temperature is a mixture of how much drink you are trying to heat, the amount of insulation and the shape of the package

 

[noagname]

This is kind of a side question but is there a program or something that would tell if you mix this and that you come out with something.

 

[lightarrow]

The handwarmers use powdered iron which oxidises when exposed to air giving off heat - it is intended to be fairly slow and low power, to give a small amount of heat for hours.
The cup heaters use anhydrous calcium chloride and water to give a lot of heat fairly quickly.

see http://www.stress.com/consumertier3.php?pid=307

In that link there is no mention of iron powder for handwarmers. Where did you take that interesting information? I only knew the method which exploits the exothermic crystallisation of supercooled molten materials (usually sodium acetate).

 

[clouded.perception]

This is kind of a side question but is there a program or something that would tell if you mix this and that you come out with something.

A decent chemistry section at your local library, if they have one.

 

[lightarrow]

This is kind of a side question but is there a program or something that would tell if you mix this and that you come out with something.

I agree with clouded.perception: what you ask is as simple as...the entire chemistry

 

[Greg Bernhardt]

I remember eating a self heating meal during a camping trip. Was quite good!

 

[noagname]

is there anyway i could buy those chemicals separately