The stupid thing I mixed today...

[eli griggs]

So, I go to mix up my very first .2% solution of benzotriazole anti-fog chemistry and, foregoing the use of my small digital scale, instead chose a RCBS 505 gunpowder triple beam scale.

Normally I am constantly checking every measure three times to make sure I am on track to my objective, and this always ends up well, however, today, I completely lost my mind and mixed 437.5 grains of bzt (1 oz.) to 500 ml of distilled water. I was shooting for 1 GRAM of bzt but somehow read the wrong table and ended up with with 28.3 g going into the bowl on my home-made stir-plate.

Well it didn't take long to see, that much bzt wasn't going to go into solution, no way no how!

I checked my work sheet and then the scale and saw my error, so, in an attempt to save the work, I increased the h2o to a total volume of 2 liters.
Now, never a bright light in the field of chemistry, I BELIEVE, that I now have a stock solution of 14.15% bzt.

How wrong am I and, more importantly, how should I dilute this to the proper solution for anti-fog application for papers?

Oh, and yes, how long should this solution be good in glass bottles?

Competent minds welcomed.

 

[Sirius Glass]

Do not ask me. I am a measure once, cut twice guy.

 

[MartinP]

The question you are asking, is what volume of a 14,15g-per-litre solution do you need in order to contain 1g of bzt - then top up that volume to one litre with whatever version of water (distilled, de-mineralized, boiled, tap-water etc.) you are using.

If I am not totally senile yet, that would be 70,67ml of the 'faulty' solution, topped up to one litre to make your working concentration of 1g bzt per litre.

Edit: now I re-read your description and see it was 1g bzt in half a litre that you were aiming for, so double the volume above ie. use 141,3ml of the 'faulty' solution, topped up to one litre, to give you a 2g-per-litre working solution.

If you want only 500ml of the working solution then, of course, just use 70,67ml of the 'faulty' solution, topped up to 500ml with your choice of water.

 

[eli griggs]

Thank you for the replies, it's helpful to hear from others.

Does anyone know the shelf life of a concentration like this, made with distilled water?

Glass or plastic, clear or dark?

Cheers