Australia's Science Forum

Hi all,
Has anybody come across this one?

[img][/img]

Our senior Chem class attempted to heat up some Magnesium Carbonate in a side arm test tube. The bunsen flame melted a hole right through the bottom of the test tube (!!!!!) Now my teacher wants me to purchaes some of the "Heat Resistant" side arm test tubes. to replace the ruined ones

Does anybody have a suggestion for a good source of Heat Resistant lab glassware? (I need to get some beakers, etc as well.)

Cheers
Ian

Ian, we have purchased those but only use them for O2 generating or gas testing for juniors without heating the tubes. For carbonate decomposition we use pyrex large t/tubes with rubber stopper and glass tubing into lime water.
A little hint. Change Mg CO3 to CuCO3 . It decomposes much quicker. Mg is very reactive.
Hope it will help.
Lada

Yes we have similar problems in the past. I specifically ordered side arem test tubes for this prac and on the first use they melted! We gave up and now use 18x150mm test tubes with a cork and delivery tube. Works well and no more melted test tubes!

Had the same problem with a batch of tubes from Serrata a while back, the bottoms were melting out. Max sent a new, tested batch, and they were fine.

Interesting because I am almost sure ours came from serata too!!

Perhaps they received a dodgy batch?

This was about 5 years ago and I haven't tried since.