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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: doncatsu on January 17, 2019, 05:36:46 PM

Title: Help with a Lab question
Post by: doncatsu on January 17, 2019, 05:36:46 PM

The problem states: "The major content of penny is actually zinc (97.5% w/w). Devise a simple experiment (no chemical reactions involved) to prove this fact."

Since we know that 97.5% of pennies are Zn and 2.5% is Cu, my thoughts were weighing a sample with 97.5 mg Zn + 2.5 mg Cu and then seeing if that weight is proportional to the weight of the penny. But I asked my professor this and he said there is a much simpler way... He simply told me: "How do you differentiate metals?" I haven't really figured it out... Any help would be much appreciated. Thank you!

Title: Re: Help with a Lab question
Post by: marquis on February 05, 2019, 08:28:51 PM

There is a large difference in density between the two metals.  Try using that to solve the problem.

Good luck.