Aluminium Potassium Sulphate, Copper Sulphate & Chemical Suppliers

[Yaglaser]

I bought a chemistry set for my sons last weekend and the instructions stated that, to do all the experiments, more copper sulphate and aluminium potassium sulphate (APS) would have to be purchased. The copper sulphate is not a problem, but the APS appears to be available in two forms: APS 12-WATER LR and APS 24-water LR. The APS in the chemistry set is 24-water (LR is not mentioned), but the type available from a supplier is 12-WATER LR. Would the 12-WATER LR be okay?

 

Also, can anyone suggest a UK chemical supplier that sells small quantities of chemicals? The smallest weight I've found so far is 500g.

 

Thanks.

Edited August 1, 2009 by Yaglaser

[Fuzzwood]

Pick the 24 water. Quantities used in the experiment are based on the molar weight (prolly in the first chapter of the manual what this means ) so with the 12 water you will introduce more of the salt than is needed.

[John Cuthber]

They are talking about the same thing but giving it two different names. It doesn't matter which one you get so go for the cheap one.

It comes from the fact that you can look at alum as

K2SO4.Al2(SO4)3 24H2O or

KAl(SO4)2 12 H2O

 

Also, I guess the experiment will be growing crystals so you will need enough to make a staurated solution. In that case Fswd's idea that you will add too much is impossible.

[Yaglaser]

Thanks for the replies. It looks as though it will be okay to buy the 12-water, then. I've only managed to find one supplier and the alum comes in a 500g container:eek: