# Need help with science experiment calculations

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1. Feb 14, 2012

### Silhou

me and my partner did an experiment of turning copper coins into 'silver' and 'gold'
we used this site or the info:
http://www.nuffieldfoundation.org/practical-chemistry/turning-copper-coins-silver-and-gold

But we're having trouble with knowing how to make the calculations of :

How much % brass, copper and steel is now in the coin after the experiment?
How much zinc dissolved and formed sodium zincate?
How much zinc was formed on the copper coin?

Can anyone please give us some suggestions on what we could do.

2. Feb 17, 2012

### ArcherScience

ok let's first start out with the first question in mind,

what was your first calculation of the copper coins? first of all, did u use actual copper coins, or straight up pennies? cause if you used pennies, its gonna be a bit difficult. if you gathered a bunch of pennies and did the experiment, then u got to notice the factor that each era of penny in the USA has different material composition. depending on its years.

here's a chart to explain:

Years Material
1793–1857 100% copper
1857–1864 88% copper, 12% nickel (also known as NS-12)
1864–1942 1946–1962 bronze (95% copper, 5% tin and zinc)
1943 zinc-coated steel (also known as 1943 steel cent)
1944–1946 brass (95% copper, 5% zinc)
1962–1982 brass (95% copper, 5% zinc)
1982–present 97.5% zinc, 2.5% copper (core: 99.2% zinc, 0.8% copper; plating: pure copper)

start off with the first calculation question, reply back and I'll see how to set this up.