Sulphur Residue: Burning Pure Sulphur

[JGM_14]

When you burn pure sulphur, what is the solid residue left behind?
I Know that sulphur dioxide is the gas that is left behind.

 

[Cesium]

If it is pure sulfur you are burning and complete combustion takes place you get entirely sulfur dioxide gas (with some trace amounts of sulfur trioxide). There is probably some impurity that is causing the solid residue.

 

[JGM_14]

The sulphur is suppose to be 99.98% pure but you can never be too sure, how do you test this?

 

[gravenewworld]

The cool thing about sulphur when you melt it is that it looks like blood.

 

[chemisttree]

You test the purity of sulfur in a variety of ways, including burning it to see if there is any residue.

Weigh the sulfur before you burn it and the residue. Then calculate 1 - (residue weight)/(initial wt.). The difference should be greater than 0.9998 if it is on spec.


The most likely impurity will depend on the nature of the sulfur. Was the sulfur in the form of large crystals or "flowers" or was it a free-flowing powder? Sometimes powders have anticaking agents added to them like talc to keep them freely flowing. Is the sulfur used to dust plants? If so, the impurity might be talc or clay. If the sulfur was originally in the form of large flakes, it could be anything... even a dirty crucible.

 

[JGM_14]

It came in the form of powder that probibly did not have an anticaking agent in it because it was kinda chunky in the package and difficult to get out.