[paul.fr]

I Remember when i was younger and had a cut, my nan would insist on putting hydrogen peroxide on the cut.

She said that if it caused bubbles, it was infected with germs. not too sure now if the hydrogen peroxide then "cured" the cut or if a cream of some sort was applied.

So my question is: Why did the hydrogen peroxide bubble, i doubt it was anything to do with the presence of germs.

[another_someone]

I would expect hydrogen peroxide (H₂O₂) to bobble when it releases oxygen (2 x H₂O₂ -> 2 x H₂O + O₂).

H₂O₂ is fairly unstable, and will easily release O₂, but what is it specifically that triggers H₂O₂ to disassociate in that situation I don't know.

[daveshorts]

There are definitely enzymes to break down H₂O₂ in your liver, and I believe that they are also in blood, so that is probably what was breaking down the H₂O₂. So I would have thought that is was blood not germs making it bubble.

[paul.fr]

There are definitely enzymes to break down H₂O₂ in your liver, and I believe that they are also in blood, so that is probably what was breaking down the H₂O₂. So I would have thought that is was blood not germs making it bubble.

That sound about right. cheers dave

[lightarrow]

There are definitely enzymes to break down H₂O₂ in your liver, and I believe that they are also in blood, so that is probably what was breaking down the H₂O₂. So I would have thought that is was blood not germs making it bubble.

Yes, one of them is called "Catalase".
http://en.wikipedia.org/wiki/Catalase

Detective curiosity: You want to discover quickly if a red stain on something (tissue, pavement, ecc.) is blood or something else. You put a drop of oxigenated water on it: if it makes bubbles, it's blood!

[rosy]

Hm, I would just point out for the benefit of people who don't know, oxygenated water doesn't necessarily mean H₂O₂ (that may be a perfectly legit way to refer to hydrogen peroxide but isn't one I'd met). More generally, oxygenated water is water (H₂O) with molecular oxygen (O₂) dissolved in it... which is not the same as hydrogen peroxide which is H₂O₂.

[Bored chemist]

Since yeast also contains catalase it might be that your red stain is raspberry juice that has started to ferment. Not the sort of evidence you want to go to court with.
Human flesh, and particularly blood, are very good at decomposing peroxides- just as well since they are by products of using oxygen and they are really quite toxic.  Most of the germs that migt invade a cut will not have this protection, so hydrogen peroxide acts as a (not very) selective germicide. Probably as much use is that the bubbles tend to flush dirt out of the cut. Clean cuts heal better.
BTW, I just saw the post above. IIRC the French term for H2O2 is L'eau oxigenee (Spelling?) I guess the Itallian is similar.

[lightarrow]

BTW, I just saw the post above. IIRC the French term for H2O2 is L'eau oxigenee (Spelling?) I guess the Itallian is similar.

Yes. I intended hydrogen peroxide.

[paul.fr]

There are definitely enzymes to break down H₂O₂ in your liver, and I believe that they are also in blood, so that is probably what was breaking down the H₂O₂. So I would have thought that is was blood not germs making it bubble.

Yes, one of them is called "Catalase".
http://en.wikipedia.org/wiki/Catalase

Catalase, that is also found in potatoes!

[Bored chemist]

Lightarrow, What's the Italian for H2O2? (It's never going to make any real difference to me but I just wonder).

[lightarrow]

Lightarrow, What's the Italian for H2O2? (It's never going to make any real difference to me but I just wonder).

"Acqua Ossigenata". More technically, "Perossido di Idrogeno".

[moonfire]

LOL  I just love it when he tutors in this language

[lightarrow]

LOL  I just love it when he tutors in this language

How it is you are so good in saying sweet things?
Hug you.