Sodium carbonate 10 water

I know this is an old query and I've seen others post photos of these 'solutions' but has anyone found a supplier of decent hydrated sodium carbonate that actually dissolves and doesn't leave what looks like a precipitate? We're trying to do the year 12 required practical to determine the amount of water of crystallisation and to be honest, I can't see how it'll work. I only started at my current school in September and there's 6 kilos of the stuff from two different suppliers and it's all the same. I'm considering biting the bullet and ordering some expensive stuff from Sigma or the like. :rolleyes:

Cheers.
 
I moved to using Anhydrous for solutions for the students and that seems to be better(so far) but we don't use a lot of it and I cant recall the cost difference of the top of my head
 
I moved to using Anhydrous for solutions for the students and that seems to be better(so far) but we don't use a lot of it and I cant recall the cost difference of the top of my head
Yeah, the anhydrous is great for making a standard solution but our guys want to use the 10 water to work out the amount of water of crystallisation. I think I may be having a persuasive word.........;)
 
Fortunately I've only needed to make up solutions for the thiosulphate "stop bath" but it is always cloudy even when made up with distilled water. I have a bucket-full (!) of anhydrous so I may start using that.
 
I've looked at the sigma online catalogue and they don't even stock the hydrated version! That tells me something. The only use I can see for the stuff we have is for the thiosulfate stop bath so at least it won't go to waste.
 
Yeah, the anhydrous is great for making a standard solution but our guys want to use the 10 water to work out the amount of water of crystallisation. I think I may be having a persuasive word.........;)
Ahh, tbh I would just let them have cloudy solutions if that's what they are insisting on and saves ordering more - call it a teaching point !
 
I've looked at the sigma online catalogue and they don't even stock the hydrated version! That tells me something. The only use I can see for the stuff we have is for the thiosulfate stop bath so at least it won't go to waste.
Just make sure the teachers know to add it slowly! I use the hydrated version for W4 disposal too so will get slowly used up
 
I know this is an old query and I've seen others post photos of these 'solutions' but has anyone found a supplier of decent hydrated sodium carbonate that actually dissolves and doesn't leave what looks like a precipitate? We're trying to do the year 12 required practical to determine the amount of water of crystallisation and to be honest, I can't see how it'll work. I only started at my current school in September and there's 6 kilos of the stuff from two different suppliers and it's all the same. I'm considering biting the bullet and ordering some expensive stuff from Sigma or the like. :rolleyes:

Cheers.

I've got an old tub of this (hidden in the back of my store cupboard so no-one else uses it!) that I keep just for this prac - but the delivery date on it is 2001, so the new stuff may not be the same quality.

It's branded with "Prime Chemicals", and labelled as "Pea Crystal" and the crystals are more translucent than white - supplied by Beecroft, it still appears on their website under the same code so MAY be the same, but may not..... It's what I'll be trying when my current stock runs out, but that may be a little while yet as they don't need much..... Our instructions tell them to pick out the "clearest" crystals to use, so very little goes for each prac..... :)

http://www.beecroft-science.co.uk/view-chemical.php?id=849
 
What we do is make up 1m of sodium carbonate solution to neutralise acids before disposal. We used to use distilled water and filter it too- but then concluded what was the point now- just use tap water and no need to filtrate either.
 
We do the titration for this. The teachers tell me they get the right results even if their solutions are a bit cloudy.
 
I make up solutions with the anhydrous Sodium carbonate, from Fisher sci.
I think the practical is one where you do a titration to work out the amount of water in the hydrated Na2CO3. I happen to be sorting that out here at the moment too.
 
We are into the students make a standard solution of Sodium Carbonate, then using it to determine the concentration of an unknown conc of HCl.
 
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