Stochiometry

Limiting Reagent Lab

Name: ___________________

In this lab exercise, you will let iron nails react with a solution of copper (II) chloride. You will determine the limiting reagent, the theoretical yield and the per cent yield of copper. The reaction you will observe is as follows:

Fe _(s) + CuCl_{2 (aq)} FeCl_{2 (aq)} + Cu_(s)

Procedure:

Day 1

1. Place a clean dry beaker on a balance and find its mass. Then, add 8.50 grams of copper (II) chloride.

2. Obtain 2 clean, dry nails. Buff the nails with sand paper to remove the lacquer. Then find the mass of both of the nails together. Record the mass on the data table.

3. Add about 50 ml of tap water to the copper (II) chloride and stir the mixture until all crystals dissolve.

4. Drop the nails in the solution and add more water until both of the nails are covered by the solution. Label the beaker with your name and put the beaker at the back of the lab for overnight.

You can go to the Processing the Data section and complete the calculations to determine the limiting reagent. You can also determine the theoretical yield of copper.

Day 2

1. Obtain your beaker. Carefully decant (pour) the iron (II) chloride solution covering the nails from the beaker into the sink. Do not lose any copper!

2. Using a pair of tongs, pick up each nail (one at a time). Using a slow stream of water from a bottle, wash all of the copper from the nails into the beaker.

3. Dry the nails with paper towel. Find their mass together and record in the data table.

4. Find the mass of a piece of filter paper, record its mass, and insert the paper into a funnel.

5. Pour the copper and solution into the funnel. Be careful not to overflow the paper.

6. Using distilled water wash the copper by filling the funnel. Do this twice.

7. Wash the copper with 25 ml of HCl. (This will dissolve any remaining iron filings)

8. Wash again with water. Then carefully remove the paper with the copper, unfold, and set on a sheet of paper towel to dry overnight

Day 3

1. Find the mass of your filter paper and copper.

2. Empty copper into beaker at front of lab.

Data:

Processing the Data

1. Use calculations to determine the limiting reagent. (Day 1)

2. Determine the theoretical yield of copper. (Day 1)

3. Determine the mass of excess reagent. (Day 2)

4. Determine the mass of copper produced. (Day 3)

5. Determine the per cent yield of copper. (Day 3)

6. Calculate the mass of copper (II) chloride which would be needed to use up all of the iron metal. (Look at the mass of iron you started with.)