Inert Metals

[akcapr]

probably the only place youd make some gold compounds is like inside a volcano or sometin

[akcapr]

again' date=' the new york state regents is messed up.

 

btw, define "laboratory conditions"[/quote']

 

 

isnt there just a universal reagent table? does each state have its own? I always though there was only one.

[budullewraagh]

new york is one of the few states that actually have regents exams. the regents are state-specific.

 

"probably the only place youd make some gold compounds is like inside a volcano or sometin"

or in some nitrosyl chloride...

[Tetrahedrite]

For everyone's information.......

Although gold is most commonly found as pure gold (and Au-Ag alloys), other gold minerals aren't all that uncommon in high temperature mineral deposits.

 

Au commonly forms compounds with tellurium, selenium, even sulfur and antimony.

 

Au-chloride complexes are extremely common in nature and are important in enrichment processes.

 

Some bacteria are even known to metabolise gold as a part of their energy cycles!!

 

So the laboratory isn't the only place Au compounds exist.

[Skye]

Is the gold in water (river or seawater) usually in forms such as halides or sulphides?

[Tetrahedrite]

Is the gold in water (river or seawater) usually in forms such as halides or sulphides?

Are you refering to "dissolved" gold, or gold in the sediments?

[akcapr]

new york is one of the few states that actually have regents exams. the regents are state-specific.

 

"probably the only place youd make some gold compounds is like inside a volcano or sometin"

or in some nitrosyl chloride...

 

i meant in nature

[YT2095]

Gold is less reactive than Silver.

 

no debate to be had, move along!

[Skye]

Tetrahedrite, dissolved gold.

[mmalluck]

Mercery will dissolve gold as well. Miners used this to leech gold out of rocks. Then they'd boil off the mercery.

[jdurg]

Mercery will dissolve gold as well. Miners used this to leech gold out of rocks. Then they'd boil off the mercery.

 

Mercury doesn't change the gold in any way, shape, or form. If it did, then simply boiling off the mercury would not leave you with gold. Saying that mercury chemically dissolves gold is like saying that water chemically dissolves salt. It doesn't. It's a physical change and not a chemical one.

 

What the miners did was rely on a physical property of gold and mercury. Gold will easily amalgamate with mercury while many of the impurities will not. As a result, it's a way to physically purify the gold. Once it has been amalgamated, they simply heat the 'solution' and drive off the mercury much like one would drive off the water in a water solution of something.

 

When aqua regia is used, however, it chemically changes the gold. It turns the gold into a soluble ion. Just evaporating off all the water/acid won't leave you with pure gold. You need further chemical refining. Therefore, it's a chemical dissolution and not a physical one.

[mmalluck]

Yeah, I know mercury and gold don't actually bond, it's just a fun fact I thought I'd throw into the mix. Most people don't know that.

[jdurg]

Heh. People wearing gold rings who work with mercury and wind up with a little spill certainly find out really quickly.

[Tetrahedrite]

Mercury doesn't change the gold in any way' date=' shape, or form. If it did, then simply boiling off the mercury would not leave you with gold. Saying that mercury chemically dissolves gold is like saying that water chemically dissolves salt. It doesn't. It's a physical change and not a chemical one.

[/quote']

 

Newsflash, water DOES chemically dissolve (soluble) salts. The chemical bonds between the anions and cations are broken, and hexaqua ionic species are formed. A chemical equilibrium is set up between the solid and the hexaqua species. The fact that an eqilibrium exists means that it is a chemical reaction, and not simply a change in state.

I think what you mean to say is that that there is no change in oxidation state ie it is still Au(0).

[Tetrahedrite]

Tetrahedrite, dissolved gold.

The main gold species in sea water is [AuCl4]-, in the parts per billion range.

[jdurg]

That is probably a better way of putting it, but still, if you evaporate the water away you end up with the exact same thing you started with. Also, just because an equillibrium exists does not mean that it's a chemical reaction. Look at the equillibrium that exists when a substance is boiling. An equillibrium is set up between the liquid phase of the substance and the gas phase. No chemical reaction is occuring at all, but an equillibrium exists.

[Tetrahedrite]

Look at the equillibrium that exists when a substance is boiling. An equillibrium is set up between the liquid phase of the substance and the gas phase. No chemical reaction is occuring at all, but an equillibrium exists.

Ahh, but this is not a chemical equilibrium, it is purely physical. You cannot have a Ksp for this reaction.

 

In catalysis, for example, you reform the catalyst at the end of the reaction. This definitely does not mean that the catalyst did not undergo any chemical reaction, and in fact we know thew opposite is true.