Given:
Mass = 2.50 g
Volume = 0.339 cm3
Find:
Density = ?
Solution:
In order to check if the penny is pure copper, we need to
find the density of the penny and compare it with the density of copper which
is 8.96 g/cm^3.
Density = mass / volume
2.50 g / 0.339 cm^3 = 7.37 g/cm^3
So, from what we got, the penny is definitely not copper. It
is mostly Manganese which has a density 7.43 g/cm3.
The properties of the
copper/nickel alloy used in the previous Susan B. Anthony dollar was intended to be duplicated by the manganese alloy, in the case of the later U.S. dollar coins.
