Sort of a Fire question, but still public safety

[Hate]

So I have a question, and it is probably better suited for a Fire related forum, but I thought of the question when I was reading about scene safety, so here goes....

Why isn't water flammable? H2O. Hydrogen is highly flammable. Oxygen while not flammable supports combustion.

So, what gives? It seems like putting water on a fire should be a bad idea when you think about it.

 

[bigbaldguy]

That's more of a chemistry question I think. From a purely don't know a damn thing about chemistry point of view it does seem a bit odd.

 

[Hate]

That's more of a chemistry question I think. From a purely don't know a damn thing about chemistry point of view it does seem a bit odd.

A firefighter friend of mine told me it's because it is a liquid. But he couldn't explain any more past that.

 

[Cup of Joe]

My guess is that when bound to form a molecule, H2O keeps the fire from getting oxygen. In order to get rid of the water (evaporate it), the fire uses more energy than it has, so it goes out. No heat, no oxygen, no fire. That's my guess anyway.

 

[Veneficus]

I suggest you look up the unique properties of water in a chemistry book.

There is more to it than individual chemical properties. It is too long to type out here, sorry.

 

[Handsome Robb]

My guess is that when bound to form a molecule, H2O keeps the fire from getting oxygen. In order to get rid of the water (evaporate it), the fire uses more energy than it has, so it goes out. No heat, no oxygen, no fire. That's my guess anyway.

Something like that.

Water displaces oxygen. To burn fire needs fuel, heat, and oxygen, take one away and it doesn't work.

Along with displacing o2 water is generally colder than fire.

I'm not very good at chemistry.

 

[Hate]

My guess is that when bound to form a molecule, H2O keeps the fire from getting oxygen. In order to get rid of the water (evaporate it), the fire uses more energy than it has, so it goes out. No heat, no oxygen, no fire. That's my guess anyway.

How can water keep the fire from getting oxygen, when Oxygen is sorta one of the main ingredients in water?

 

[Hate]

Something like that.

Water displaces oxygen. To burn fire needs fuel, heat, and oxygen, take one away and it doesn't work.

Along with displacing o2 water is generally colder than fire.

I'm not very good at chemistry.

This sounds like it might be right, but if it is because water is cooler than fire, why don't we use ice, or dry ice or something colder?

 

[Nervegas]

I think this should help answer this question:

http://www.physlink.com/Education/AskExperts/ae481.cfm

Google is your friend.

 

[Cup of Joe]

How can water keep the fire from getting oxygen, when Oxygen is sorta one of the main ingredients in water?

because hydrogen and oxygen cannot be separated by heat.

Table salt: Na+Cl, two pretty dangerous elements on their own.

 

[silver]

because hydrogen and oxygen cannot be separated by heat.

Table salt: Na+Cl, two pretty dangerous elements on their own.

You sure about that?

You need 458.9 kJ of energy per mole to break a O-H bond in H20.

 

[Hate]

I think this should help answer this question:

http://www.physlink.com/Education/AskExperts/ae481.cfm

Google is your friend.

This article doesn't really answer anything. The site you linked me too is basically yahoo answers for people with physics/astronomy questions. it is a forum just like this one.

the first guy tries to answer by likening water to table salt. when you consider that table salt is an ionic compound, and water is covalent, the two are hardly comparable.

The second guy basically says "you cant burn/combust things that aren't burnable/combustible", akin to saying that you cant do something because you cant

 

[Cup of Joe]

You sure about that?

You need 458.9 kJ of energy per mole to break a O-H bond in H20.

I thought that was using electrolysis, not solely heat.

 

[Nervegas]

This article doesn't really answer anything. The site you linked me too is basically yahoo answers for people with physics/astronomy questions. it is a forum just like this one.

the first guy tries to answer by likening water to table salt. when you consider that table salt is an ionic compound, and water is covalent, the two are hardly comparable.

The second guy basically says "you cant burn/combust things that aren't burnable/combustible", akin to saying that you cant do something because you cant

The first one is saying that once the individual atoms are bonded together to form a compound, that they no longer retain the characteristics of the individual atoms themselves.

The second answer is stating that H20 is already the product of combustion and therefore does not combust itself, rather, at high temperatures, it merely changes states, to a gas etc.

 

[firetender]

It's the "2" that messes everything up?

"H" and "O" would be dangerous if they weren't separated by it.

 

[Hate]

The first one is saying that once the individual atoms are bonded together to form a compound, that they no longer retain the characteristics of the individual atoms themselves.

The second answer is stating that H20 is already the product of combustion and therefore does not combust itself, rather, at high temperatures, it merely changes states, to a gas etc.

Can you explain it? I mean in different words, the second part seems analogous to defining a word with the word. you cant because you cant?

 

[Hate]

It's the "2" that messes everything up?

"H" and "O" would be dangerous if they weren't separated by it.

The whole "more is better" principle heh :rofl:

 

[Shishkabob]

Sodium is dangerous. Chlorine is dangerous. Sodium chloride is yummy.


Yay electrons.

 

[Hate]

Sodium is dangerous. Chlorine is dangerous. Sodium chloride is yummy.


Yay electrons.

you do realize that's not helpful, and has already been stated several times?

MMIZ recently made an entire thread about not posting when you have nothing worthwhile to say.

 

[Sandog]

I thought that was using electrolysis, not solely heat.

Joules is a just a measurement of energy, ability to do work. Energy is energy whether it be heat or electricity.
The H-O-H bond is a strong bond and requires energy to release it. If one were to throw water onto a fire, the water would absorb the heat, transition from liquid to vapor and rise since H-O-H molecule is lighter than O2 molecule.

During the water boiling point, the water does not explode because the energy from the fire is not sufficient to break the HO bond only enough to change the state from liquid to vapor. Now if one were able to superheat water, it would explode.

Water is used on fires because it absorbs heat and breaks the fire triangle.