2w ago

How much silver powder (by mass) is in this beaker?

I'll be drying the silver out and weighing it sometime in the next couple days. Closest guess when I do gets bragging rights! (And absolutely nothing else)

The scale was zeroed with the beaker empty, and it contains only water and silver (and a trace amount of copper nitrate). If you have a strategy behind your guess, please do share it!

47 comments

Density of silver: 10.49g/mL Density of water: 1g/mL Total mass: 1464g Total volume: 700mL x = volume of silver, mL y = volume of water, mL 10.49x + 1y = 1464 x+y = 700 9.49x=764 x=80.5058mL of silver 10.49x = 10.49 × 80.5058 = 844.51g of silver
Probably an over estimate [of just the silver] due to the copper so probably more like 835-840g. [If just evaporating, the mass would be higher due to the lower density of the impurities like copper sulfate, so more around 845-850g. E.g. 5mL of copper sulfate would be 830g of silver and 18g copper sulfate = 848g]
- Damn, you were faster than I was, I was just calculating the same thing. All I have left is to assume that they won't be able to fully dry the silver and guess a bit higher... 850g.
  
  Unfortunately for you, I've got a hot plate and it gets pretty darn hot.
- Unfortunately you weren't the closest (ended up being 817g and some people undercut you) but I will give you the award for most sensible calculation.

250ml solution (mostly water on top) = 250g
700g (if 700ml water) - 250g = 450ml silver slurry
450ml silver powder weight (dry) = 1800g
1464g (total) - 250g (excess water) = 1214g
450ml slurry = 1214g slurry
1800g (dry silver) - 1214g (silver slurry) = 516g (516ml water in slurry)
1464g (total) - 516g (water) = 948g silver powder.
I always miss something obviously stupid when doing math in public. However, it sounds suspiciously close to a 1kg starting weight of silver though.
- I always miss something
  Yes, in the very last line, it made no sense anymore (and I bet you felt it in your gut).
  It should not be:
  1464g (total) - 516g (water) = 948g silver powder.
  but rather:
  1214g (silver slurry) - 516g (water in slurry) = 698g silver powder.
  
  Damnit. I edited with that correction, but deleted the edit, cause who the fuck knows why. Was kind of in a rush at the time, and didn't think I would have been silly enough to miss the 250g.
  Good cach and yeah, I felt it.
- 1800g (dry silver) - 1214g (silver slurry) = 516g (516ml water in slurry)
  What? Why? I'm kind of sure that this is wrong (subtracting (water + silver) from silver can't get you water, you could get (silver - water) at best) but I'm interested in the reasoning here because it short circuit my brain.
  
  I'll walk through it again, as you are probably right, and I can find the mistake.
  1800g is the estimate weight of 450gml silver powder.
  The total weight is 1464g.
  There is 250ml (g) of water at the top of the container, which we subtract from the total weight, leaving 1214g of a silver/water slurry.
  1800g should be the weight
  1214g is the weight.
  (Here is the mistake) The weight difference is 516g, which is the weight of the missing silver in the slurry, not the weight of the water in the slurry.
  So, I would need to convert 516g to an approximate volume of silver powder. Since we have volume, we can now compute the weight of the water in the slurry.

830g.
People already did the work for me , so I'm playing The Price Is Right is my methodology.
- 829g
  
  Congrats, you got it, ended up being 817g. I think the real winners are the people who actually did the calculations though. :)
  
  Congrats!

Fuck it, 1 kg exactly. I will accept the silver as my reward.
- Damn, you were faster than me.
  
  Pew pew

At least twee fiddy
- It was about that time I noticed that nice little amateur chemist was a three story tall crustacean from the Mesozoic!

No more than 1.4 kgs!

30g, not educated. Just a guess.
- 31g Bob!
  
  Under cutting, fucker! You're not allowed at Price is Right game night..../jk

1102g - took a stab at the density of micron-sized silver powder, the volume, then arbitrarily knocked off 30% for the saturation in water 🤷

1026g. Based on the amount of visible water volume, and a guess of more above that subtracted from the total weight.

Thanks for your guesses, everyone! The final dry weight turned out to be 817g.

~~How much? Weight or volume?~~
I assume you mean weight.. Give me a sec and I'll take a guess.
- Yeah I meant mass, but that's a fair question. I updated the title.
  
  Nah, it was kind of a dumb question actually. The volume isn't going to change much unless you melt it down. Thanks though!

0.01 g. That's just beach sand.

Is that elemental silver or some fancy compound?
- Just elemental silver.
  
  Elemental, my dear Watson

980g, no calculations, just riding off the coattails of people who did more work than me.

I love that so many people know how to do this.

What's the context of this photo? I.e. what were you making/processing?
- I'm chemically refining some 90% silver coins I had into pure silver. I first dissolved them in nitric acid, then added copper to selectively precipitate the silver.

Similar method to previous poster but I'm guessing 979g.

844.4 grams of silver.
- I'm gonna bid $1, Bob.

500g

47 comments