Boiling Saltwater

Life takes its toll, even for the halophile...

But here comes another blog post.

Adding salt to water will increase the water's Boiling Point.  What this means is that it takes a higher temperature to make the water come to a boil.  At sea level, water boils at 100 ºC (212 ºF), though at higher altitudes the boiling point of water decreases, and vice-versa, due to some other non-salt-related phenomena.

The reason that salt increases the boiling point of water is fairly straightforward.  Salt (NaCl), as I've mentioned previously, is an ionic compound.  Many ionic compounds (particularly those including sodium) are soluble in water, which means that they dissolve.  When salt, composed of sodium ions and chlorine ions, dissolves, it breaks down into its individual ions.

These ions are nonvolatile, which means that they do not evaporate.  Instead, they just absorb heat energy which would otherwise be absorbed by the water (H20).  Now, you might think that this means that you can add any old thing (like a shoe) to boiling water to "steal" its heat, and that's true... but all you'd accomplish is to make the water to take longer to boil.  Once it reaches 100 ºC (or a slightly different temperature depending on where you live), it's going to boil.  Adding salt to water makes it boil at a higher temperature, which has its benefits.

This guy knows.

 

Whatever temperature water boils at is as hot as that water is going to get (in its liquid form, anyway).  Gaseous water can get pretty dang hot, but unless you're cooking with a pressure cooker (which also raises the boiling point of water, by the way), all the steam that your boiling water produces is just going to cool down right away.  The benefit to increasing the boiling point of water is that it allows you to achieve higher temperatures, which means that you can cook your food faster or more thoroughly. 

If you're at a high altitude and your water boils at a temperature that's too low to adequately cook your food, you can add salt to raise the boiling point.

To give an idea as to the effect of salt on the boiling point of water, here's a data table produced by a fourth grader from Mankato, Minnesota six years ago (I like to have credible sources):

Ionic Compounds

Let's take a moment to talk about ionic compounds, as I think this might come in handy for future posts.  I'm admittedly not the best person to talk about chemistry concepts, but I'll do my best not to say something completely untrue.  Here goes:

Ionic compounds are chemical compounds usually consisting of positively charged cations bonded with negatively charged anions or polyatomic ions.  The key here is the ionic bond -- a pretty standard bond to wrap one's head around, since it functions on the attraction of positive charges to negative charges.  Something like magnets, I guess.

(Crap.  Now I need to define cations, anions, and polyatomic ions...)  So they're all ions, if you've noticed, which means they have an unequal balance of protons and electrons, the positive and negative components of atoms, respectively.  Cations are positively charged atoms, anions are negatively charged atoms, and polyatomic ions are molecules (I have to use this term loosely) of an unbalanced charge (very often negative).  Molecules are just groups of atoms, like or unlike, and they are supposed to have a neutral charge.  Polyatomic ions consist of specifically unlike atoms, and of course they're not neutral.

Okay.  The part I really want to get to is the other name that ionic compounds go by...

SALTS.

Sodium chloride is an ionic compound, and apparently it's everybody's favorite, because now all ionic compounds are sporting its name.  It's certainly the most delicious.

Here are some other ionic compounds that we ingest:

• Sodium Flouride: found in toothpaste (which you shouldn't eat) and tablets to prevent cavities.
• Ammonium Chloride: used in cough medicine; as a food additive; and in something called "Salty Licorice" (which doesn't contain table salt, but Ammonium Chloride is a salt).
• Potassium Iodide: used to supplement table salt with iodine, to help prevent iodine deficiency.
• Calcium Chloride: used as a food additive and firming agent.

I'm sure the list goes on.  That was only four, obviously.

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Anyway, this is all supposed to be a briefing for some future subjects I'd like to discuss.  My definitions were all a bit rudimentary, and no doubt muddled (I doodled my way through chem class), so you might consider taking a trip to Wikipedia.  Like this page, for example.