Chemistry of common things

From Helpful
(Redirected from Water)
Jump to: navigation, search


Cooking

Doughs

See Doughs, batters, leaveners

Greenery

Trees, O2, CO2

Water

On hydration

Drinking slowly?

3 liters a day, or less?

Coffee

Alcohol

On bottled water

On filtering water

Demineralized and distilled water

Distilled water is nearly-pure H2O, because distillation means you move the water and leave behind most other things


Demineralized water means few to no minerals (fresh natural water has some, tapwater has a more-controlled bunch; see also hard water) by some method

...but says little about what else may still be in there
it's useful to keep minerals out of chothes irons, car batteries, and such (largely to avoid limescale)


On contents of demineralized water

Demineralized water often mentions it is not fit for consumption

in practice it's usually pretty clean water, but it's not guaranteed to be pure
largely because depending on the process of demineralization, there may be other things still left in there, say, a few bacteria. Your iron or car battery won't care, but you might
and because it doesn't matter for the intended uses
(also in part because it's also sold in supermarkets, so it's useful, possibly required, to point this out explicitly)


Does distilled or demineralized water lead to nutritional deficiency?

On water poisoning

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Most of your body contains something like 0.15% salt, and blood 0.9%.


Water poisoning happens when drinking a large amount in a short time, because of what it does to certain balances in your body, primarily salt and other electrolytes.

If you manage to dilute your body significantly, it starts affecting cellular function in general.

If you manage to dilute your blood significantly, it's part of that mechanism that dilutes your body.


You will probably notice this poor function because it leads to headache, poorer muscle control, possibly vomiting and diarrhea.

The fact that you will feel bad, and have probably associated "I feel bloated, I probably need to stop drinking water" is why most people are at negligible risk.

(though if you confuse it with "I'm dehydrated, I need to drink water", that's not great)


Time is a significant factor,

in part because drinking only moderately more than you need, your kidneys are perfectly happy just making you pee a lot more
Which wastes some salt in the process, but not very much(verify)
in part because because it takes a while for you to absorb water you drink, basically while it's in your gut
(related to why moderately fast rehydration in hospitals is done via saline IVs - it's in multiple ways more practical than something the relies on timing and attention(verify)).

The time factor is why you see statements like "stay under 3-4 liters of water within in a few hours".


Doesn't distilled water do this a lot quicker?

No.

Quickly drinking liters of almost any water based drink will do this, basically because most water based drinks are almost entirely water.


Sure, tap water has things beyond H2O, including sodium. As does bottled water. The concentrations of these are very low (order of roughly 0.003%(verify).

...and in practice those are more related to tasting like the water you're used to, because these amounts are very low relative to the amounts we need.

e.g. for salt, it is primarily the salt we add to our food that helps us keep our salt balance, and your cravings will typically guide you to a decent amount of salt (actually, many of us get a little too much salt).


It's also not really how much other-things there is in it, it's how much of that changes the osmotic pressures between it and your body (called its osmolality).

But even if all of the additives in tap water were relevant, the difference between that 0.003% in tap water and 0.000% in distilled water is basically negligible to you drinking it.

...because both are significantly lower than your body's 0.15%. It's one or two orders of magnitude lower. In a practical sense, both are basically zero.


There's a difference you probably measure in lab conditions, but that's about it.

If you're stranded in a desert for weeks, and have the choice of what water to take, maybe, but still not really, in that it'd be a lot more important to catch the salt you sweat out.

And it might actually make a real difference what the non-distilled water is. If it's not regulated tap water, the possibility of pathogens may be a lot more important)


Water hardness

This article/section is a stub — probably a pile of half-sorted notes, is not well-checked so may have incorrect bits. (Feel free to ignore, fix, or tell me)

Fluoride in drinking water

Salty water

Electrical resistance of water

See Electronics_notes/Resistors#Resistance_of_fluids

Oxyhydrogen