Part I: Making the Copper Sulfate Solution

You will need to create 25 mL of a 0.25M solution of CuSO4 in 3M HCl. Using your 100 mL graduated cylinder collect ~ 25 mL of 3.0M HCl from the front counter and place it in a beaker. Be Careful!

Using the weighboats provided, weigh out the correct amount of CuSO4 you calculated in your pre-laboratory assignment. Be sure to use proper weighing technique.

Fill the volumetric flask about 1/3 full with 3.0 M HCl. Add a small amount of HCl to the weighboat containing your CuSO4. Slowly pour the HCl/CuSO4 slurry into the volumetric flask. Add HCl to the CuSO4 in the volumetric flask until the volume is 25 mL exactly as indicated by the white line on the flask. Allow the solution to return to room temperature. Check to see that the volume is still correct. Add a little more HCl if necessary.

Part II: Precipitating Cu2+ Ions as Copper Metal

Collect and weigh all of the following items and record the masses in your notebook to the nearest 0.0001 g.

1. A 100 mL side-arm flask
2. 4 or 5 pieces of solid zinc metal (weigh together on a clean Kimwipe)

Place 25 mL of the copper sulfate solution in the sidearm flask and re-weigh. Record the mass in your lab notebook to the nearest 0.0001g.

Collect a balloon from the front counter and fit it onto the sidearm of the pre-weighed flask. Using a rubber band or parafilm, make sure the seal of the balloon to the sidearm is airtight.

Collect a stopper from the front counter. You can add parafilm to the flask before adding the stopper to guarantee a good seal.

You are now ready to start the reaction. Quickly place the pre-weighed zinc metal pieces into the solution and cap with the stopper. You should see bubbles form right away. This is the hydrogen gas being produced.

Make observations about how the solution’s appearance changes as the reaction proceeds, noting if there are any color changes. Make sure the balloon stays on the sidearm of the flask as increased gas pressure might push it off.

When the reaction is complete (no more bubbles and the solution should be clear) you will need to carefully measure the balloon. Record the diameter in your notebook.
Make observations about the solution and the metal pellets in the flask.  Specifically, detail how these observations may support the claim that a reaction took place.

Finally, remove the balloon, stopper and parafilm from the flask.  Reweigh the flask and its contents and record the weight in your notebook to the nearest 0.0001g.

Dispose of the solution and pellets in the appropriate waste container(s).