BlazeBall - 20-9-2011 at 07:22
I've heard this term being applied to reagents for sale, but what does "synthesis grade" actually mean in terms of purity? There seems to be so many
different terms used.
ScienceSquirrel - 20-9-2011 at 07:49
To be honest this means whatever they want it to mean.
Something that is easy to purify and is very stable may be very pure, while something that is harder to deal with may be a lot less pure.
Supppose I am making ferrous sulphate from steel wool 98% pure and drain cleaner sulphuric acid 95% pure.
After one or two crystallisations from deionised water my product will be be something like 99+% pure so I won't care about the crap in my starting
materials.
You can take a percentage to the bank, almost everything else is meaningless unless it is BP, USP, etc that is defined in the formulary. 
BlazeBall - 20-9-2011 at 08:03
Thanks for the info. One of the chemicals I was looking at is HCL.