Zinc and Lead Acetate Lab

Behavior of solid Zinc in an aqueous solution of Lead acetate
Introduction:
What mass and mole relationships are there in chemical reactions? Stoichiometry is the
calculations that can be done with balanced chemical equations. Now that we have learned how
to balance chemical equations, we will put our new knowledge to the test and calculate amounts
of products and reactants based on our equation.
In this experiment, you will find the mass of a sample of solid lead acetate
(Pb(CH 3 COO) 2 3H 2 0) and prepare a water solution of it. You will also find the mass of a zinc
strip, place it in solution, and observe its behavior. By finding the mass of the zinc strip at the
close of the experiment, you will be able to investigate quantitatively any changes that occur.
Procedure:
Part I
1. Obtain a strip of zinc. If it has been used before, clean it with steel wool or emery paper until a
shiny surface is obtained.
2. Mass your zinc strip. Take a weighing boat and zero out the scale.
3. Mass 1.500 g of lead acetate into your weighing boat.
4. Transfer the solid lead acetate to the 250-mL beaker. Add 200 mL of distilled water to the lead
acetate and swirl gently until the entire solid dissolves. Add a few drops of concentrate acetic
acid to clarify the solution.
5. Place the zinc strip in the beaker and make sure zinc is completely covered.
6. Observe for several minutes and record any changes that take place. Cover the beaker with
parafilm and let sit overnight.
Part II
1. At the beginning of the next class observe the beaker and record any observations in your
notebook.
2. Remove the parafilm and remove the zinc from the solution (use tweezers if necessary). Use
your wash bottle to wash all of the lead crystals off the zinc piece. Make sure to get all the lead
off. Set the zinc aside on a paper towel to dry. When it is dry, find its mass.
3. Let the lead settle in the beaker. Carefully decant the solution. Decant means to pour off
liquid, leaving the solid behind. Wash the residue with 10 mL of water and carefully decant.
Wash and decant at least three more times. Finally, wash the lead with 10 mL of acetone and
decant once again.
4. After the final washing, the residue must be allowed to dry.
5. Mass a clean piece of filter paper and filter the lead into the filter paper and glass funnel. Use
the acetone wash bottle to make sure all the lead gets into the filter paper. Allow the filter paper
to dry.
6. Once the lead residue and paper are dry, mass the paper and lead to determine how much lead
was produced.
5. Dispose of the lead properly and clean the beaker. Wash your hands and clean up your lab
station.

Calculations
1. Calculate the change in mass of the zinc strip.
2. Calculate the mass of lead obtained.
3. Calculate the number of moles of zinc reacted.
4. Calculate the number of moles of lead produced.
5. Determine the ratio of moles of Pb/ moles Zn.
6. Calculate the moles of Pb(CH 3 COO) 2 3H 2 0 used in the experiment.
7. Determine the ratio of moles of Pb/moles of Pb(CH 3 COO) 2 3H 2 0.
8. How many individual atoms of zinc metal were involved in the experiment?
9. How many individual atoms of lead metal were involved in the experiment?
10. Calculate the theoretical yield of Pb from the amount of lead (II) acetate used.
11. Calculate the percent yield.
Conclusion
Write the balanced chemical equation including states of matter for this experiment and then
compare your coefficients to your answers for #5 and #7.