Hey everyone. I'm playing around with reversal these days and I'm having trouble mixing my STS.
I used the following formula, gleaned from this post of Charles Scott's: https://www.icmag.com/ic/showpost.php?p=6997987&postcount=1 regarding the difference in weight of the anhydrous and pentahydrate forms of sodium thiosulfate. I have pentahydrate.
0.1M Sodium Thiosulfate solution = ~2.5g Na2S203 + 5 H20 in 100ml of distilled water.
0.1M Silver Nitrate solution = 1.7g AgNO3 in 100ml
mix 20ml (0.02M) Silver Nitrate solution + 80ml (0.08M) Sodium Thiosulfate solution.
Each solution is clear, but when they're mixed, an odd reaction occurs, giving me what appears to be Silver Sulfide (Ag2S, a grey/black precipitate) that eventually settles out. Initially I thought it was a problem of being exposed to light, but given the solid precipitate, I suspect there's some sort of imbalance in my ratios or contamination of some kind. I've washed the containers I've been using and rinsed them well with the same distilled water I use for the solution.
Unfortunately, ions were always my stumbling block with chemistry. I'll keep doing my own research, and post anything I learn here, but any thoughts about what might be going on would be greatly appreciated.
I used the following formula, gleaned from this post of Charles Scott's: https://www.icmag.com/ic/showpost.php?p=6997987&postcount=1 regarding the difference in weight of the anhydrous and pentahydrate forms of sodium thiosulfate. I have pentahydrate.
0.1M Sodium Thiosulfate solution = ~2.5g Na2S203 + 5 H20 in 100ml of distilled water.
0.1M Silver Nitrate solution = 1.7g AgNO3 in 100ml
mix 20ml (0.02M) Silver Nitrate solution + 80ml (0.08M) Sodium Thiosulfate solution.
Each solution is clear, but when they're mixed, an odd reaction occurs, giving me what appears to be Silver Sulfide (Ag2S, a grey/black precipitate) that eventually settles out. Initially I thought it was a problem of being exposed to light, but given the solid precipitate, I suspect there's some sort of imbalance in my ratios or contamination of some kind. I've washed the containers I've been using and rinsed them well with the same distilled water I use for the solution.
Unfortunately, ions were always my stumbling block with chemistry. I'll keep doing my own research, and post anything I learn here, but any thoughts about what might be going on would be greatly appreciated.