q: about weights & volume in different states of Au

[steyr223]

How is everyone
crystalemmaava you have my best wishes

Here we go
Curious : say I put 1 ounce of Au in 100 ml's of Hcl (combined with bleach)
The weight of just the solution + 1 ounce would be the total when the Au was in its elemental state sitting at the bottom of the beaker. Is this right?
What would differ once the Au was dissolved?
Also when dropped back out still in the solution
(Powders)
I know volume also plays a Big part in the give and
Take part.
One more : my 1 ounce dropped out powders before
melting, there weight. Would be 1 ounce?
Thanks Steyr223. Rob
PS. I would try it but don't have an ounce of Au :lol:

 

[tek4g63]

The reaction caused while dissolving the gold causes some off gassing. I would assume that there would be some weight loss of the solution due to this off gassing, although minimal. Then maybe some weight added when you add your precipitant to drop your gold, although this too causes off gassing..........

I'm only typing my thoughts on this as I think them. I'm sure there is another member that could better answer this question. I am now curious too!

 

[Drowningbodacius]

Off gassing will cause a minimal amount of loss if you add the bleach in large quantities. To prevent the off gassing when I do the HCL/cl method is use a pipette and add the bleach a table spoon at a time by the drop while slowly stirring the au it takes a while but there is no off gassing due to bubbling of solution. I just did a batch last night of 6 grams and had 6 grams fall. Also you should weigh your au dry so you can do a correct ratio of 1 to 1 of your smb. Those are my thought on the question but I'm sure someone has mire info about it

 

[Geo]

the weights of gasses compared to solids or even liquids couldnt be measured by the average person or even most labs. since gas has volume and weight, it can be measured. a small amount of liquid or solid makes a very large amount of gas. there are exceptions as with most things. when you add SMB, the off gasses compared to the weight in salt is so one sided, it would be hard to measure the weight in SO2 released.

putting gasses aside, a solution should weigh the total of the components added. gold weighs the same no matter what state its in, even gas. when you turn a liquid or solid into a gas, weight is not as big an issue as volume.of course all this is relative to atmospheric pressure. at greater pressure, liquids will hold more gasses, lower pressure means less gasses.

on a side note. geologist believe that gold metal starts out as a gas or vapor that is forced up through the earths crust. where the gas or vapor passes through the right type of stone (crystal quartz), it condenses into a metal.

 

[MysticColby]

I think this is what you're asking...
it you have 1 oz of gold and dissolve in 100ml of HCl and bleach solution:
1 oz gold = 28.35 g (you might be using troy, I don't know, but I'm just giving an example here so it doesn't exactly matter)
37% HCl has a density of 1.19 g/L
bleach has whatever density it has... depends on your source and it's concentration. let's assume the density of both mixed together is 1.19 g/L, this is an example afterall

you dissolve 28.35 g gold in 100 ml HCl/bleach
the volume will increase a little, but not as much as the volume of gold you add (maybe you'll end with 101 ml of liquid)
the density of the liquid will increase due to heavy metal gold now being in solution:
100 ml * 1.19 g/ml = the liquid before weighs 119g
the liquid after will weigh 119g + 28.35g = 147.35
this 147.35g is spread over 101ml, so the density of the dissolved gold solution is 147.35/101 = 1.459g/ml

offgassing would play into this, but the effect is so minimal you would never be able to measure it except with an analytical scale (we have a few at work, they're fun to use: you can put 1ml water on it, it will read 1000.00 mg, then slowly decrease about 0.01 mg every 10 seconds or so due to evaporation)

adding SMB is a very complicated reaction involving several molecules and simultaneous reactions. I know the reaction is on one of these posts around here...

If you started with 1oz of 24K gold, you could end with about 1oz of 24K gold. You'll lose some due to liquids sticking to beakers, etc. but experts tend to have very low material lost. As you gain practice you'll get higher recoveries.
Then again, I know some people at work that are OK with losing 20% of their yields due to neglect... they just don't care and/or aren't careful enough to do better. (we don't work with metals at work, but it's a relatable practice/princible)

 

[steyr223]

Thanks that is the info that I wanted
So if I weigh my solution before the addition
Of Au and then again after with the proper
Calculation you should be able to be real close
To your smb needed
A little off topic but I'm just typing my
thoughts as they come to mind :idea:
Thanks Steyr223 rob

 

[MysticColby]

wouldn't it just be easily to weigh the gold going in?
If you don't know the content, isn't that one of those things you should know before processing? (in case of inquartation needed or tin presence or ...)

I should also add that you would lose some weight due to evaporation of water (if heated or you can see steam, evaporation can add up)