InFormation - 18-12-2010 at 16:47
I know this is going to sound extremely stupid, but it's something that I can't find an answer to:
Example: I have X amount of solution of Y% (lets say, 200mL of 30% HCl). Does that 30% represent the percentage by weight, volume or number of
molecules in the solution?
Also, what does it mean when the amount of moles if written on a reagent in solution: is this a constant thing (x moles per mL or something), or the
total amount of X in a full container of it?
Thanks in advance.
gsd - 18-12-2010 at 17:04
Generally when percentage is mentioned, it is specified whether it is weight/weight (w/w) or weight/volume (w/v).
when you say 30% HCl it is w/w, even if amount is specified in volume. ( At least this is how I interpret it.)
Assay of dissolved reagent in a solvent is specified as molar solution. eg when you say 2 M grignard, it means 2 moles of grignard reagent in 1 lit
solution.
On a container of pure reagents generally, both net weight as well of Molecular Weight is mentioned. So there is no need to note moles separately,
gsd
InFormation - 19-12-2010 at 14:36
Thanks! 