Making Fire from Ice

[SA Friday]

You should have posted this months ago!

On a side note, I understand boiling to be a cooling process that restricts water from being heated passed 212 degrees Fahrenheit *depending on atmospheric pressure*. I don't understand why water won't boil without impurities. Know any more about this?

H2O can be heated to it's boiling point and is technically boiling even though there isn't bubbles forming in the liquid. The gas is being released off of the surface. The bubbles are a result of surface tension around particles in the liquid. That's why when you add something to distilled water at boiling or above temps, you get the splashee splash everywhere. You can see the same thing in a slower phase by putting a spoon in water almost at boiling and touching the bottom of the pan. You get bubbles off of the spoon, mostly on the bottom. Molecular polarity comes into play here, but I will skip it and save you the . This is going into chemistry and physics molecular theories. I love this stuff, but it's really complicated and all theory.

So, back to water. H2O will absorb heat until it reaches it's boiling point and then levels out at that temperature until all of the H2O molecules have reached the boiling point. Then you see a rise in temperature again. The temp will continue to rise and the phase change to gas will continue at a faster and faster rate until the reaction/phase change is complete. The same thing happens in all elements and pure compounds, and freezing points of elements and pure compounds in reverse. Altitude/pressure and what elements are in the compounds all affect boiling and freezing points.

Some compounds have very low boiling points and in the lab we add these little chips of ceramic to them to ensure the bubbles form when testing boiling points as they are pure or close enough to pure. If you don't, you get the same anomoly as with the distilled H2O, but now you are dealing with potential dangers other than just hot water. Boiling hydrochloric acid everywhere is a bad day and a trip to the emergency shower.

This anomoly is called a flash boil. It can happen at room temp in some cases. The most common is mixing water and acids and bases. The enthalpy of the reaction during mixing can cause enough heat to flash boil if done improperly. That's why we always add acids and bases to water and never the other way around. It's also why we use a stirring stick to run the acid or base down into the water. It stops it from flash boiling.

If you want to really understand the phase change in water (solid to liq to gas) look up a water phase diagram and read about it. There's actually a point where pressure and temp can effect other instant phase changes in water. If you want to see this do a search on youtube for 'boiling water at -20 degrees'. You should find a lot of vids on this almost instant phase change. Oh ya, cold water can be turned into ice without making it colder by pressurizing it too. If you want to get really deep into it, look up colligative properties. Be warned though, some of this stuff will cause your head to hurt.

[Irving]

So without impurities, the water is still technically boiling, just without bubbles? And water can be heated passed 212 without adding pressure?

[AGC]

distilled, pure, H2O will react like this at 212 degrees F. It doesn't exactly explode, but reacts quite violently. Other pure substances do this also, but not many. H2O is just flat out weird stuff chemically, and is most dense when in it's liquid state. I can't remember why pure water reacts violently when heated, but I think it had something to due with the density and being molecularly polar.

Regardless, don't try this. You get boiling hot water everywhere. Someone could lose an eye or skin or something. Then where would you be; all physically deformed and the neighbor kids will make fun of you and call your Freddie... No good can come of this.

It's lack of nucleation points.

The water is superheated (past the boiling point), but surface tension is preventing the formation of steam bubbles.

Anything that disturbs the surface tension---a spoon, sugar, instant coffee, etc---will provide the nucleation points that allow the formation of steam bubbles and the superheated water will flash into steam.

[hollohas]

So without impurities, the water is still technically boiling, just without bubbles? And water can be heated passed 212 without adding pressure?

I believe adding salt to the water will change the boiling point. Boils at a higher temperture without added pressure. Just like if you put salt on ice it melts, the salt raises the freezing point.

SA Friday, correct me if I'm wrong, seems like you payed attention in school. Thermodynamics, chemistry and the likes all make my head hurt so I have blocked those classes out of my memory as much as possible...5 years of studying engineering and I don't remember much.

[Irving]

5 years of studying engineering and I don't remember much.

That's how I feel about my major. It's kind of embarrassing for me actually.

[SA Friday]

I believe adding salt to the water will change the boiling point. Boils at a higher temperture without added pressure. Just like if you put salt on ice it melts, the salt raises the freezing point.

SA Friday, correct me if I'm wrong, seems like you payed attention in school. Thermodynamics, chemistry and the likes all make my head hurt so I have blocked those classes out of my memory as much as possible...5 years of studying engineering and I don't remember much.

Adding salt raises boiling point and lowers freezing point. These are two of the four colligative properties of aqueous solutions.

The salt disassociating on the ice causes the water on the ice to have a lower freezing point. There is also an exothermic reaction (enthalpy) involved with some salts during disassociation and this can cause the ice to melt and continue the reaction. Magnesium chloride (that's the stuff CDoT sprays on the roads here) is one type of salt that does this.

I'm currently going to Metro for a BS in Chemistry, Criminalistics concentration. I average about 40 hours a week in the science building, all of that in the chemistry wing. My Gen Chem teacher calls me a 'chemistry whore'. The more I learn the more I want. I don't always get everything right, but I'm still learning.

[Irving]

I've been trying to convince a chemistry major to put nicotine into a sports drink for years now. "Smoke at your desk!"

We'll be billionaires.