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=
`(mass)/(\rho)`

Using the formula

Volume of copper=
`(63.546)/(8.96)=7.09 cm^3`

Volume of zinc=
`(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.