Sciencemadness Discussion Board

Preparation of Barium

trinitrotoluene - 29-11-2002 at 23:19

I am curious about this method.

Reacting barium oxide BaO with Al or Si

3 BaO+2Al > 3 Ba+Al2O3
Correct me if i am wrong. I think its like the thermite reaction.



[Edited on 26-3-2005 by chemoleo]

rikkitikkitavi - 30-11-2002 at 08:26

that means that for the reaction deltaH is
-31kJ as written (or -10,33 kJ/mole Ba)


Hr = -1675 - (3* - 548) = - 31 kJ

I wouldnt call it a thermite reaction, since the reaction only produces very little heat compared to a standard thermite reactiion.

You have to look at the Gibbs free energy for those compounds to se if it is a spontaneous reactionn (i e possible)
The same calculation is made with Gibbs free energy for the compounds. If Gr > 0 it is a spontaneous reaction, i e it progree to the right as written in the text.

Spontaneous doesnt mean that the reaction starts by itself, you need to add enough activation energy to get it started, f e x by a external heat source, then the heat released will make the reaction progress.

In this case, since the heat output is so low, I would assume that the reaction will quench immetiately if the heat source is removed. How much heat and more important, how high temperature I cant tell. But I guess you have to heat it to atleast 1000 C before anything happens.

/rickard

vulture - 30-11-2002 at 13:42

You'll need protective and totally inert (noble gas, Ba reacts with N2) from begin to end, as barium reacts with all gasses in the atmosphere, even at room temperature. That's why it's often used to create extreme low pressure vacuum.

BASF - 30-11-2002 at 16:30

You need quartz glass(up to 1710°C).
It´s not that expensive as one would think.

trinitrotoluene - 30-11-2002 at 16:53

Is there different way to get Barium like electrolysis of Barium Salts? If so which ones would you suggest?

Jstuyfzand - 11-7-2016 at 09:18

Quote: Originally posted by trinitrotoluene  
Is there different way to get Barium like electrolysis of Barium Salts? If so which ones would you suggest?


From the wiki, Barium Chloride.

blogfast25 - 11-7-2016 at 09:38

Electrolysis of a barium salt aqueous solution with a mercury cathode, followed by distilling off the mercury from the amalgam (under vacuum or argon) should work.

[Edited on 11-7-2016 by blogfast25]