Question

If the density of copper (Cu) is 8.96 g/cm3 and that of zinc (Zn) is 7.13 g/cm3. Calculate and compare the volume of a pre-1982 penny to that of a post-1982 penny? Give one reason to support your answer

Answer 1

Answer with Explanation:

Density of copper(Cu)=$\rho_{Cu}=8.96g/cm^3$

Density of zinc(Zn)=$\rho_{Zn}=7.13 g/cm^3$

Atomic mass of copper=$63.546 g$

Atomic mass of zinc=65.38 g

We know that

Volume=$\frac{mass}{\rho}$

Using the formula

Volume of copper=$\frac{63.546}{8.96}=7.09 cm^3$

Volume of zinc=$\frac{65.38}{7.13}=9.17 cm^3$

Volume is inversely proportional to  the density.

Pre -1982 penny made by copper and post-1982 penny made by zinc.

Therefore, volume of post-1982 penny is greater than the volume of pre-1982 penny because density of zinc is less than the density of copper.