Spontaneous Combustion

[grayfalcon89]

Here is my question.. How would regular steel wool go under spontaneous combustion or simply combusts by itself? I mean that you can't like burn it in the lab or throw it to the fire. This was the question in last exam. If it helps (it didn't help me; my teacher told us the "translated" version of the question), here is the original question.

 

Under what conditions might iron (steel wool in this case) undergo spontaneous combustion? (If you are reasoning clearly from what you have observed and predict a logical answer to this question, your teacher will verify your answer with a sparkling demonstration).

 

Thanks for your help!

[Cap'n Refsmmat]

There's nothing in there saying that it has to spontaneously combust without outside "help" (i.e. a blowtorch).

[jdurg]

If plunged into an atmosphere of Chlorine gas, steel wool will ignite quite readily. Same with an atmosphere of Fluorine gas, and possibly Bromine as well.

[grayfalcon89]

Can this be an answer (I like the second response though.. but I have no clue on how my class would've talk about this.. :-?)

 

If you soak steel wool in oil and not discard it properly, it may undergo spontaneous combustion. I remember reading these in many labels.

 

Or is it soaking in water..?

 

I know it's either of them. Can anyone clarify?

[woelen]

Theoretically, steel wool could ignite spontaneously. Very finely divided iron is pyrophoric. But I've never heard of steel wool igniting spontaneously. With oil the chance is reduced, when it is humid, I can imagine that this increases the chance of ignition, but still, I think the chance is VERY low. If this could happen more easily, then certainly in the overly safety-aware US this product would be banned from the shelves.

[jdurg]

In reality, the steel wool into a flask of elemental Chlorine is a pretty standard demonstration and one that your teacher would be able to do. In addition, it is quite "sparkling" as the iron ignites and begins to "burn" in the Cl2 atmosphere.