so i had a lab in chemistry, and this was one of the questions i didnt know how to answer. can anyone help me with this please? New pennies are actually made of copper and zinc. design an experiment for determining the % of Cu and % Zn in a penny. write out the procedure in distinct steps
I'll leave it to you to work out all the details for your procedure, so here's the gist. There is no acid which will react only with the copper cladding on a penny. Therefore, you can mass some pennies, and then dissolve them in nitric acid to make a mixture of Cu2+ ions and Zn2+ ions. Then essentially repeat your copper lab by adding NaOH and then warming it to make CuO, and decanting the solution containing all the other ions. You'll drag the zinc ions along as Zn(OH)2 initially, but it won't matter. Dissolve the CuO and any zinc compound in H2SO4. At the last step you will add zinc metal to replace the copper. Recover the copper metal, wash it and allow it to dry. Then mass it. Determine the ratio of the mass of the copper metal to the mass of the pennies, and express the fraction as a percentage. Subtract the percentage of copper from 100 to get the percentage of zinc.
