Posts Tagged ‘cause’

Potassium explodes without Hydrogens help

June 20, 2011

Thus far almost all the stuff I’ve done on the alkali metals has been on ~250 mg quantities.

Self preservation says, “Start Small!”, and with good reason, the reactions of alkali metals with water are known to scale in treacherous fashions.

In the first instance I went for 1.6 g of potassium and 3.5g of sodium.

Note here there is not the slightest hint of green gas with the potassium!

Now the potassiums the one I’m going to focus on for the moment, simply as when this is played back at about 1/100ths speed it becomes clear that the hydrogen burning plays essentially no part in the violence of this reaction.

Fascinatingly the explosion appears to go in two stages here!

So potassium, molecular weight ~40, so 1.6 g is 0.04moles. 2moles of potassium gives a mole of H2 , so this reaction will produce about half a liter of hydrogen.  Just for scale the jug is about 3 liters.  It’s also fascinating to see the ‘springiness’ around this generated gas.

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