concentrated cobalt chloride

[lab-woman]

Hi Everyone,
My senior chemistry teacher has asked me for a concentrated cobalt chloride solution with 70% water and 30% metho. So....how much of the cobalt chloride do I actually weigh out for the "concentrated " 100ml solution? This is for a yr 12 prac.
Help....

[ELIZABETH]

I found this....maybe it will help

[Jazz]

for equilibrium prac,as a demo, all you need is
cobalt solution - 1g of CoCl2.6h2O in 10 mL of 2 - propanol. Then add water drop wise until the deep blue solution just turns pink ( in the test tube or 10 mL specimen jar)
1 ice bath
1 water bath at 100 degrees C

[sunray18]

generally for saturated solutions - go to the Chemical data book - or the internet and look for the solubility OF THE COMPOUND. I t will be given in gms per 100 mL at 20 deg C.. that is the maximum weight of the compound that will stay in solution at that temperature in water. I boil the water and add a little more than this weight per 100 ml, stir until dissolved then cool the solution - and you have a saturated solution.- THAT IS IN water ONLY..

[lab-woman]

Thanks heaps everyone. Ended up going with Jazz's equilibrium prac. Worked a treat. Gotta love chemtalk!!