Are there any two chemicals that when mixed, cause fire?

Question

Are there any two chemicals that when mixed, cause fire? I mean without violent explosion or possibly fatal fumes. I am just interested in knowing (no I'm not a pyromaniac.)

Answer 1

Small amounts of Sodium metal placed in water will flame.  Too much Sodium might cause a small scale explosion, but, more than likely, you're fine if you only use a couple grams.

Actually, any alkali metal will ignite with water, only anything further down the table than Sodium and you're pretty much guaranteed an explosion.

Answer 2

Glycerine and potassium permanganate.  

Answer 3

Iron sulphide (FeS) when in contact with Oxygen (air) is 'Pyrophoric' in that it will Auto-ignite with no other outside influence.

This substance is extremely dangerous as I know from experience in the Oil and Gas Industry.

Equipment used in Oil and Gas operations involving H2S and Water Vapour become internally coated with FeS and, when being opened for maintenance, cooling water is used on the FeS deposits to prevent the combustion reaction and all flammable gases are first purged out with Nitrogen before opening the equipment.

Answer 4

This is one of my favorites, but the reaction is pretty violent, so PLEASE BE CAREFUL!

Molten Potassium Chlorate (melt it in a test tube over a Bunsen burner USE A STAND!!)  and a gummy bear.  Drop the gummy bear into the potassium chlorate WITH TONGS NOT YOUR FINGERS!

Or, check it out on youtube.  Search for "screaming gummy  bear"