I'm labelling solutions of chemicals and notice that Appendix D uses a lot of percentage solutions and not molarities to classify whether the chemicals are orange or green (DET talk for 11-12 or 7-12). Just want to check that I'm heading in the right direction. For example barium hydroxide has a molecular weight of 315.47 so that mean 315.47g per L = 1M? Which then means that my currently green labelled bottles of 1M and 0.5M barium hydroxide should really be orange instead, because they are 30% and 15% solutions respectively?
I've got 1.0M Barium hydroxide at 171.3g in 1 litre of water. But that's comming from a card that was written out before I arrived (>15yrs) I'd say still green.
Yes, the MW of Ba(OH)2 is 171.3, but that still gives 1M an orange dot. Solutions of barium hydroxide are orange at concentrations greater than 1% (0.05M), according to Appendix D.
Thanks macca and Whspa,
I found a chart on Wikipedia (of all places) that listed the monohydrate as MW 171 and the octohydrate as MW 315. Started scratching the head thinking - how do I figure out which one I have. Then I thought to read the label on the solid in the Chemical store! (Just looking for a smiley with a light bulb moment or one with blonde hair.)
Anyway, the label said Octo and had the MW was 315 so I now have two orange labelled bottles of Ba OH2.
Am I ever going to get good at this??
Thanks again.
Regards,
Patti
