Before $1982$ U$.$S$.$ this economically unfeasible, so after $1982,$ pennies were made with a zinc center and ath coating of copper on the outside. Pennies minted in $1982$ were of both types.

In this lab you will take advantage of the fact that zinc reacts with hydrochloric acid and copper does not.

PROCEDURE:

Using a triangular file, make a small notch in three places around the edge of a post$-1982$ penny. These notches should be deep enough to expose the zinc inner core as shown to the right. Mass the penny on an electronic balance and record your data. Place the penny in a $50mL$ beaker, labeled with your initials, and have your teacher add $20mL$ of $6MHCl.$ As soon as you add the acid, you will see a chemical reaction start to occur. Place the beaker in a safe place overnight.

After $24$ hours, pour off the acid as directed. Gently rinse off all the acid from the penn Place the shell of the penny onto a piece of folded filter paper while you dry out your la beaker. Then place the penny and filter paper into the beaker and allow it to dry overn When the penny is dried, mass what is left of it$.$

DATA:

Mass of penny before reaction $2\mathrm{.}47g$

Mass of penny after reaction

CALCULATIONS $($SHOWALL WORK$)$:

Calculate the mass of the penny that was:

A$)$ Zinc

B$)$ Copper

Calculate the percentage of each metal in the penny:

A$)$ Zinc

B$)$ Copper