Brass pennies and so much more

Janderso

Janderso

Jeff Anderson
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You’ve probably seen the High School chemistry experiment where they turn pennies to gold? (Well brass coated anyway)
I thought I’d give it a shot. It’s really easy.
After I coated the copper pipe I realized there may be more possibilities here.
Copper with a zinc coating?
Anything copper can be coated with zinc and therefore heated to a brass color.

Edit. If you decide to try this, the boiling sodium hydroxide fumes are nasty. Plenty of ventilation and use a respirator that can handle organic vapors and acid gasses. P100+
 

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If you want to process olives you use lye to get the bitterness out.
At least that's what I've done. There is a salting process that is used to cure olives as well.
That's the only thing I can relate to lye and food??
 
woodchucker said:
Sodium Hydroxide is Lye, so why is there food grade Lye?
Click to expand...



It's not so much that it's "in" the food you eat, but it's part of the production process. It gets "used up" in the process. It does all kinds of magic, but the one I remember is that it attacks protiens in bread, it's what pretzels and bagels get "dipped" in before cooking. But when the reaction (and maybe the cooking?) is complete, it's gone. Not there anymore.

I'm not sure if it's this lye or the other one, potash, (Potassium? Hydroxide), but some lye is involved in the automatic fruit peeling process where they literally dissolve the skin off of it...

If you think that answer sounds like it didn't come from a chemist or a chef, you're probablly about right on both counts. But the takeaway is that when you see "food grade" where you think it doesnt belong, it's because of the definition of "food grade". Food grade doesn't mean you can drink lye water, it just means that it's free of contaminants, so if it's used as it should be, you're not gonna get some other poisonous or toxic residue left behind after the original poisonous toxic thin has been consumed by it's reactions.

Oh yeah, I forgtot ice cream.... It's involved in that somehow too.
 
Here's the spiel from the kitchen-improvised chemistry book:

Brass is a copper-zinc alloy. An alloy is a mixture of two or more metals dissolved in each other when molten (or a metal and non-metal fused together). The percentages of copper and zinc in brass vary depending on the type of brass. These differences allow the penny in this activity to turn several different colors. When a copper penny is added to the zinc solution, the zinc ions migrate to the copper where they are reduced to metallic zinc and deposited. The silver coating on the penny is the gamma form of the brass alloy with zinc content greater than 45%. This gives the penny its silver coloring. When the zinc-coated penny is heated, the penny becomes gold in color. The gold color is due to the zinc migrating through the copper to convert to the alpha-form of brass alloy which has a zinc content of less than 35%. This form of the brass alloy is a golden color.
 
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