Turn Pennies Silver and Gold (Chemistry Trick)

In this video we turn copper pennies into silver and finally to gold.
Obviously it's a chemistry trick but still impressive.

First we get 30g of zinc sulfate and dissolve it into 100mL of water.

Zinc sulfate was made back in our video on making a copper sulfate and
zinc battery: http://www.youtube.com/watch?v=Id3tL2iI0Vw

If you don't have zinc sulfate or can't make it, you can also use zinc chloride. This can be made by simply mixing hydrochloric acid with zinc metal and waiting until the fizzing stops.

Then we drop in several cut strips of zinc metal.

Zinc metal was obtained from our video on getting useful materials from batteries: http://www.youtube.com/watch#%21v=knc1lSupAwQ

The solution is heated to a boil and copper pennies, that have been thoroughly washed/cleaned, are dropped in. They must touch the zinc in order for this reaction to work. Leave it in for five to ten minutes.

The zinc metal dissolves and releases electrons that go into the copper and give it a negative charge. The zinc ions in solution now redeposit form a thin layer of zinc metal. Giving the coin a silvery color.

Now the smart physical chemist might wonder how this can possibly work. Overall we're going from zinc metal to zinc metal and at first it seems like we're missing something about thermodynamics. What is the driving force? I've searched the literature and there doesn't seem to be a consensus among scientists, some claim it's a surface free energy issue with zinc having a lower potential on copper than in free solution (at high concentration). Others state that its an alloy of zinc metal and copper on the surface. The silvery color you're seeing on the penny is actually a type of white brass, not pure zinc. This is thermodynamically more favorable than pure separate metals and thus serves as the driving force.

Anyway, whatever the specific chemical reason, we've now deposited zinc onto copper.

The most amazing trick is to turn it into gold. Simply wash the coin and place it on a hotplate heated to about 300 Celsius. As it heats the zinc will diffuse into the copper, forming brass on the surface that looks like gold.

Eventually it will wear off but the results are rather impressive.

Category:

Education

Tags:

• Chemistry
• copper
• silver
• gold
• pennies
• trick
• science
• fair
• experiment
• zinc
• sulfate
• electrochemistry
• redox
• magic
• brass
• galvinization
• alchemy

[UkrainianDragon1993]

Dr. NurdRage, could you please make a video on how to shine pre-1982 copper pennies? There are a lot of ridiculous videos out there using ketchup and soda that don't even work. I have hundreds of these old pennies and I want to make them shine :)

[NurdRage]

@UkrainianDragon1993 react them with a mixture of vinegar and salt. After they brighten up, wash off the acid and dry them with a paper towel before the acid ruins them again.

[kopi0hun]

Ah, in hungary we dont have copper coins...

[NurdRage]

@kopi0hun this will work with just about any piece of reasonably pure coppper. Wires are an easy to get source.

[s0ccurpr0]

Love the videos but one question. I'm looking online for zinc sulfate, would zinc sulfate monohydrate work?

[NurdRage]

@s0ccurpr0 yes

[flamesRules]

Get thousands of pennies.

Turn them gold.

Put them on ebay.

?????

Profit

[DAKINGOFMUSIC343]

i put my figure of BUDA and its gold

[rockmyroll99]

You've dont it! You are a true alchemist! FInally, all these years of finding answers, you've made gold!

[thomas242007]

hey its john from delocated

[JIZZYJAY3697]

You've Got The Deepest Voice In The World.

[PaulOrientedotcom]

Good chemical trick



[ausaf86]

one quwstion can u plz tell me how much zinc and coppor nEed to turn it into a BRASS, WAT OHRT THING WE CONNA USE FOR IT PLZ REPLY

[kakitembak23]

1 question

can we use the electrochemistry method?

[jose45615]

Is that your actual voice or a voice over

[tvmalk]

But can you make 1's into 100's?