Turning copper into ‘silver’ and ‘gold’

Turning copper into ‘silver’ and ‘gold’

Posted on by Victor McDonald


In this demonstration we appear to
change a base metal, copper, firstly into silver, and then into
gold. The silver is actually just a layer of zinc
plating and the gold is brass, an alloy of the
copper and the zinc. The first thing we need to do is clean
off a copper coin. I’m going to use some wire wool to clean the copper coin off. Be careful when you use wire wool because the small pieces can break off and get into the skin. You might prefer
to wear a pair of gloves or to use a different mild
abrasive. So we need to get the copper coin nice and clean. The next step is to make a
solution of sodium zincate. I’m going to do that by
adding five grams of zinc powder into 100 cm
cubed of 6 mol per dm cubed sodium
hydroxide solution. I then need to heat the solution to boiling. The bubbling you can see is partly due
to the hydrogen being given off from the reaction between the zinc and the sodium hydroxide which is quite unusual and shows the amphoteric nature of zinc, the ability to react with both acids and alkalis. Take the Bunsen out while
there’s still some zinc left in the bottom of the beaker. That’s important because the plating stage of the process is actually an electrochemical reaction and the copper needs to be in direct
contact with the zinc in the bottom of the beaker. Pop the coin into the solution so it’s in contact with the zinc at the bottom. After a few minutes the copper coin will be coated in
a silvery grey layer which is the zinc. If I just lift it out. The next step is to rinse the coin off in some cold water. This cools the coin down and gets rid of the sodium zincate
which is important for the next stage. If possible try and do this stage under a running tap and then just dab the coin dry, and we make sure that we take off any lumps of zinc that have stuck to it. You can see that we’ve changed our copper coin into silver The silver is actually a plating of zinc which if
you think about it is quite unusual because the electrode potentials, the order of the reactivity series of the
metals, would lead us to predict that zinc should displace copper from its compounds not the other way around, but by complexing the zinc we’ve actually changed the order of the
electrode potentials. The next stage is to change the silver into gold. Put the coin in the top part of the Bunsen flame and very gently heat it. Don’t overheat it because the
metal will tarnish and you can see before your eyes the silver changing into gold. The gold is actually a layer of brass which is formed by the zinc
diffusing or migrating to the surface layer of the copper.

    • 100 thoughts on “Turning copper into ‘silver’ and ‘gold’”

    1. Found this channel at least today! Subscribed immedialy, my daughter will love it too. Mcu better way to learn chemistry then in school 😉

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    13. It's a much more attractive title "Turning Copper into Silver". I highly doubt anyone would actually believe that you can actually do this, so they probably just clicked to see what trick was being proformed.

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    16. whatever it is filled with is what it is. As the same sense of in bread of humans….. just sayin… you aren't changing the metals. It's plated and not solid

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    23. I have watched your video 3 times and i could not understand why you call a chemical
      Zn-plated silver and a Zn-thermal oxidation cold.Do you mean the colours?

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    34. This is misinformative about what alchemists did – a base metal was straight out of smeltered stone (ore) – the base metal (for example pig iron) contained impurities – such as silver or gold – scientists are very detached from nature – its like they think the pure alchemical products they work with just occur naturally like packaged steaks in tesco.

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    37. Omg you performed alchemy! tell me, what do you know of the philosopher's stone? Me and my brother alphonse must find the stone in order to get our bodies back!

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    41. It is not really sliver or gold, its a zinc and brass layering it just looks like gold and sliver. Could you imagine how worthless gold and sliver would be if you could create it this easily. (btw if you listened carefully she told already told you)

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    45. I did this at school several times for the new kids to show them some chemistry-tricks 😀 Was always cool to see the effect. But the Zn-Solution smells pretty bad. When i watched the video I instantly had this smell in my nose 😀 (after 10 and more years)

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    53. This blew my mind to see zinc plate out onto copper! Usually it's the other way around. I purify precious metals for a living and this one caught me off guard. I also didn't expect zinc to dissolve in strong base. Keep sending cool videos like this one!!

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    54. Glad to see this demonstration. I performed this experiment properly ONCE. Thereafter it always failed. I think it was because I used mossy zinc, or it could have been because I did not have exposed metallic zinc with which the copper could react. US pennies since 1973 are zinc with a wash of copper. I've wondered — but have have not tested — if mild heating would cause the zinc core to react with the copper to produce a layer of brass. If so, it would be beneath the copper on the surface, but should be tougher than the copper itself. Have you ever played with this?

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    58. i wonder how many people have tried to pass off copper as silver or gold this way for scams.
      As a kid i discoverd if i put U.S. pennies in my shoe, the sweat that bleed through my socks would cause it take on this really cool iridescence almost like an oil slick. I wonder if it is a similar reaction as this.

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    66. we are supplyier of zinc powder and zinc chloride solution if any body looking we have better supply origin from China cheaper price.

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    72. this is alchemy!! you didnt actually turn anything into gold or silver. you couldve cut all the complication out and just spray painted it! its basically the same thing.

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    79. While I was doing this for my chemistry project, I accidentally breathed in some of the fumes whilst the sodium zincate was boiling. It tingled my nose a bit, but am I safe?

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    82. My name is zaidi I wanna talk to you about your video pl if you have a time can I call you your whatsapp numbers my WhatsApp num 00923371440777 your WhatsApp num pl send me or call me thanks

      Reply

    84. Or chem teacher did this experiment but said he would not tell us what happened to turn it a gold color. Thanks for explaining it.

      Reply

    92. Funny, the China just pronounced their scientists can change copper into gold this morning. A day after Christmas 2018.

      Reply

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