[medic770]

Hey all,
I'm a little rusty on my chemistry, but we were discussing some of the substances we have around the station today, and one of them is "magnesium sulfate anhydrous" (in instant hot packs). Now, I get the "anhydrous" part - so my question is: if you simply add water, does it become plain old "magnesium sulfate"?

Thanks!

[Fluorine]

Magnesium sulfate with water would form a hydrate - magnessium heptahydrate, I think. This means the magnesium sulfate is surrounded by, in this case, five water molecules. This is different than mixing something in water as a hydrate can remain solid.

However hydration process is exothermic, meaning it will release heat. Depending on the quantity and how quickly you mix them will determine the extent of heat produced.

http://en.wikipedia.org/wiki/Hydrate

[medic770]

Gotcha.

I cut the bag open, dumped the anhydrous MgSO4 onto a paper plate and put some sterile water on it to see what happens. It got warm, and went from a very fine powder to a solid hunk of crystal-ish stuff.

Thanks!

[Fluorine]

For future purpose, especially if you hydrate more, it would be safest to use a pyrex glass container (or something else borosilicate) if possible (nonreactive and thermal resistant). Glad it worked out though.

[Borek]

magnessium heptahydrate, I think. This means the magnesium sulfate is surrounded by, in this case, five water molecules

Hepta and five don't look good together.

[Fluorine]

I mean seven, sorry!

Today is not my day. I review my statements before posting yet I'm making obvious mistakes. Though penta/hepta always get switched around in my head if I don't think about it for a moment.

[Borek]

Don't be too hard on yourself. As long as you are capable of seeing you were wrong you are not lost