Will my solution degrade if left out?

[Bluenoise]

THis is just a quick question. I have a solution of ~0.01M primary standard Potassium iodate (KIO3)made up that happened to accidently get filled past the mark on a volumetric flask. So my question is if I leave it out for a couple of nights in a dark place to evaporate down to the mark will I loose a noticible amount of KIO3

[BenSon]

My teacher is a bit of a narc about these things so she would probably say empty it out and fill it again...but if you don't want to do that then I would use a pipette to suck a small amount out rather then let it evaporate as the solution would become more concentrated if you do that because the water will evaporate and the potassium iodate will not.

 

~Scott

[jdurg]

The problem is, leaving it open to the air will allow contaminants such as nitrogen oxides, sulfur oxides, and carbon dioxide to dissolve into the solution which can and will alter the concentration of the KIO3.

[Bluenoise]

AH I see I see. Why would I suck it out with a pipette? Sure it'd look better? The idea is to evaporate it and get it more concentrated. Because I put to much water in which diluted it to much.

 

I think I'm just going to weigh a new sample. An hour in the oven isn't much really, it would have been nice to have it free though.

[budullewraagh]

jdurg.....there are hardly any nitrogen or sulfur oxides in the atmosphere... and only 1% of the CO2 will dissolve, 1% of which would form H2CO3.

[jdurg]

jdurg.....there are hardly any nitrogen or sulfur oxides in the atmosphere... and only 1% of the CO2 will dissolve, 1% of which would form H2CO3.

 

Tell that to any detector or person living anywhere near LA, NYC, or any major road. Also, based upon the molarity of the primary standard the concentrations would be very crucial. If you worked in an analytical lab and left a standard open to the atmosphere, or mis-made it, it would be a pretty big deal even with those little bits of contaminants.

[budullewraagh]

well i had assumed he wasnt an employee at an analytical lab...and he lives in toronto. the atmosphere is not so bad over there :\

[Silencer]

Just take out enough so that it is back to the line, then measure how much you took out. You can then mathematically determine how much KIO3 you need to add to get the concentration right.

 

It will probably be an extremely small amount though. Like, so small it's negligible.

[BenSon]

Why would I suck it out with a pipette? Sure it'd look better? The idea is to evaporate it and get it more concentrated. Because I put to much water in which diluted it to much.

 

Yeah sorry that was dumb of me for some reason i thought you had poured premixed solution in to much...Your doing the right thing just making a new one...

 

~Scott

[jdurg]

It's better practice to just make a new solution. You don't want to get into the habit of just 'fixing' a messed up solution. It's a bad habit to start and can lead to problems later on in your chemistry career.

[budullewraagh]

KIO3 is expensive:\

i wouldnt blame the guy if he wanted to try to purify his solution

[H2SO4]

i dont know much about KIO3, but could you possibly slowley boil the solution to make it more concentrated, but would this make it the KIO3 decompose or somethin, otherwise this would work.

[budullewraagh]

you could concentrate it by boiling a solution of it, yes. if you heat it excessively, it can decompose, but if you are reasonable at it, you're ok