Warning: Copper Acetate is highly toxic, preform this
experiment only if you have proper safety precautions.
In the previous video I showed you how to make Copper Acetate, using Copper Sulfate as a precursor. Today, I will show you how to make Copper Acetate from Elemental Copper, in our case pennies. To do this experiment we will need two glass containers, distilled white vinegar, and 3% Hydrogen peroxide solution. In addition I recommend getting a notepad, and one scale. While we prepare this experiment a brief history lesson is needed. Modern pennies are made of mostly Zinc, with only about 2.5% copper to coat the outside. However, they weren’t always like this, prior to 1983 they were made of 5% Copper. So in our experiment we will prove this, while also synthesizing Copper Acetate.
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Step 1: Step 1: Gather Materials
You will need to gather:
Distilled white vinegar
3% Hydrogen Peroxide
Copper, in our case pennies
Step 2: Step 2: the Reaction
First, both beakers will be filled with about 27 grams of pennies.
In each beaker, the pennies were separated such that one beaker was filled with pennies made previously to 1983, and one with pennies made after 1984. These beakers were filled with equal parts Distilled Vinegar, and 3% Hydrogen Peroxide. What you will see is the evolution of Oxygen gas as the reaction proceeds. These two solutions were allowed to react overnight and then the insoluble impurities filtered off, using a coffee filter.
Step 3: Step 3: Recording Data, Explanation, and the Science!
After filtration there is a stark difference between the two
solutions. The solution made with more copper is a much deeper blue, indicating there is a much higher content of Copper Acetate. There was a recorded loss of 1.23g in the pre-1983, and 1.95g in post 1984. The mass lost is greater in the newer pennies, why? The best explanation I can come up with is that the Copper was oxidized more so in the newer pennies. Copper Oxide is insoluble in water, and thus is left behind during the filtration step. As you can see here the black copper oxide is removed with a little bit of force, proving that the majority of the copper was oxidized, rather than forming copper acetate.
Here is the science behind what happened:
Peracetic Acid Equilibrium
H2O2 + CH3CO2H ⇌ CH3CO3H + H2O Reduction of Copper metal by Hydrogen Peroxide, and the synthesis of Copper Acetate 2Cu + 4CH3COOH + 2H2O2 → [Cu2(H2O)2(CH3COO)4] + 2H2O
Step 4: Step 4: Which Method Do I Use?
As for the two methods used, the Copper Sulfate method
produces more pure copper acetate, as well as in higher quantities in a cheaper method. This is a fun way to create Copper acetate though, and would only be cheaper if you had the scrap copper for free.