Are You Worth Your Weight In Gold?

Aim: To attempt to turn a copper coin into a silver/gold one.





Equipment:
- Two small beakers, 50ml and 250ml
- Bunsen burner/other heating things
- Heat Mat
- Tweezers
- Zinc Sulfate,
- Zinc Metal
- Glass Stir Rod
- Tap Water
- Copper coins



Method:
*DISCLAIMER, Actually read these, carefully. We didn't the first time and it didn't work as well*

1. Set up the bunsen burner, be safe!
2. Fill the smaller of the two beakers 3/4 full with tap water, this is your cooling beaker, set it aside.
3. Dissolve 30 grams of zinc sulfate in a beaker with 100ml water. A little heat from the bunsen burner will speed this up.
4. Place the zinc metal in the beaker, enough to cover the bottom.
5. Using tweezers, place a couple of copper coins into the solution. Make sure the coins are touching the metal pieces but NOT each other.
6. Bring the solution to a slow boil for about ten minutes.
7. Carefully remove the pennies with tweezers, placing them in your cooling beaker then drying them with a paper towel. They should now be silver!
8. To turn them gold, carefully heat them over the bunsen burner until a brassy/gold colour.
9. Recool it and boom! Gold coin!

Results:
WE DID IT! It only took us two separate hours but we did it! Look at this! Look at our success!

"It look pwetty" - Chyna 2019

"I'm a wich(rich) kid" - Also Chyna 2019

 "Money Money Money" - Also Aldo Chyna 2019

Discussion:
When a "copper" coin is placed in a zinc solution, the formerly copper plated steel coin becomes zinc plated and appears silver to the human eye. When the coin is heated, the copper and the zinc form an alloy of brass and appears gold.
I say "copper" because the coins aren't technically made of copper. The coins we use are actually copper coated plated steel, giving them a copper colour. Now, steel is an alloy of iron and carbon. Speaking of alloys, we're going to talk about them now. Why? Because coins are made of alloys... and we used coins in our experiment... now I feel like this meme...

I've talked a lot about alloys but what are they? What are they useful for? Well, an alloy is a mixture of two or more elements, where one (or more) of which is a metal. Alloys are made and used because of the advantages they have compared to pure metals, like how some alloys are stronger/harder than the metals they contain. A commonly used alloy is steel. As mentioned before, steel is an alloy of iron and carbon, with stainless steel with additional nickel and chromium, and tungsten steel with additional tungsten and chromium. It is used in bridges, ships, building frames, and cars because of how it's stronger, harder, and more flexible than iron. It also doesn't corrode (eat away at) as fast as iron. Other common alloys include bronze, brass, and duraluminium (duralumin?)

Other than alloys, this experiment can be connected to electrochemical cells. What is an electrochemical cell? I'm not entirely sure how to explain it but this is what Google says...
"An electrochemical cell is a device capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions."

In an electrochemical cell, the more reactive metal loses electrons, this is called oxidation, and the less reactive metal gains the lost electrons, this is called reduction. For example, let's say we take two beakers. When we put a piece of zinc metal in a Zn²⁺ solution and a piece of copper metal in a Cu²⁺ solution inside of these beakers, eventually, because of how reactive zinc is, it will become Zn²⁺ and 2 electrons. As stated before, the more reactive metal, Zinc, will lose these electrons. The less reactive metal, being copper in this example, gains the two electrons lost by the Zinc. The Cu²⁺ will turn into Cu. What Chyna and I did was basically this but in one beaker. Boom. Science. 
(*ANOTHER DISCLAIMER* please be aware, I'm a year 10 student and this is year 13 work. Don't crucify me)

Evaluation:
If I were to do this experiment again, I would use a different set of equipment, or at least swap the metal for a powder.
What we noticed was that because we used zinc metal, rather than zinc powder, the reaction occurred a lot slower than people who used zinc powder. In a short, simple, form, this is basically because of the surface levels of our materials. Because the metal had less contact with the coin, only parts of the coin were touching it, compared to the powder, which completely engulfed the coin, the reaction occurs a lot slower. Rates of reaction and such.

Instructions are taken from:

https://www.sciencecompany.com/Turn-Copper-Pennies-Into-Silver-and-Gold-Pennies.aspx
Thanks, guys!