Chemistry Honors – Class 11

Coinium

Dates

• Periods B, D: Tuesday, September 16th
• Period G: Wednesday, September 17th

Activity – Coinium

• Background: prior to 1982, U.S. pennies were made of mostly copper (approximately 95%), with the remainder being made of zinc. After 1982 the composition was changed to 98% zinc, with a copper shell. This change was made for cost reasons.
• Your challenge: given a mixture of older and newer pennies, can you determine how many of the pennies are of each type?
• Procedure notes: You will be given access to a stash of older and newer pennies for reference. NOTE – you should verify that the pennies you pull form this stash are of the proper year. Your known sample (please record the assigned letter) of “coinium” contains 27 pennies ,which you are not allowed to count. However you may empty the container to find the mass of the container, as well as the mass of the container with the pennies. Be sure and show all work appropriately in your LNB, including data, calculations and results.
• Question: What does this have to do with isotopes?
• Q: What is data? What are calculations? How do I show each of them in my LNB?

New Material – The Atom

• Table summaries: Z, A, p, e, n, charge, symbol
• Practice: Ch. 2 (67, 68)