Day 140: A Penny Saved is a Penny Dissolved


IS I students are looking at periodic trends and today we focused on Group 11 and the “noble metals.” After notching a post-1982 penny to expose the zinc core, the students placed the pennies in 3.0M HCl overnight. They massed the pennies before and after the HCl dunk. They were all surprised to find the pennies are less than 3% Cu. We discussed the low reactivity of the Group 11 elements, their use as coinage, and their antibacterial property.



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