Copper-Iron Exchange Challenge Lab

The Copper-Iron Exchange Challenge Lab

In this exploratory you'll study the reaction of iron with copper (II) sulfate (CuSO₄). The iron will replace the copper, forming solid copper and a solution of iron sulfate as products. The reaction can be visualized as:

iron (s) + copper (II) sulfate (aq) -> copper (s) + iron (?) sulfate (aq)

BROWN SOLID + BLUE SOLUTION -> REDDISH SOLID + CLEAR SOLUTION

Iron is capable of forming compounds with a either +2 or a +3 charge. It will be your task to determine whether iron (II) sulfate or iron (III) sulfate is formed. [Sulfate is a polyatomic ion : a group of atoms that act like a single charged particle. It is SO₄ with a -2 charge.]

The basic technique used here is that of limiting reagents. Two balanced equations for the reaction between copper (II) sulfate and iron, showing both possible products, will show you the mole ratio of copper (II) sulfate to iron needed to produce each possible product. From this you can determine the mass ratio of reactants needed. You will then carry out trials of the reaction using both ratios, and qualitatively observe them to determine which reactant is used up completely (the limiting reagent) and which remains (the excess reagent) in each case.

STEEL WOOL
Requirements:

You are required to run at least 3 trials at each of the two ratios.

The class is limited to a total of 20.00 g. copper (II) sulfate.

All students must be involved in doing the lab, and must be capable of explaining how to calculate the mole and mass ratios. There will be a postlab quiz (8 pts.).

Present this lab orally, to me. Assume I know as much chemistry as you do, but am not familiar with this particular lab. I expect to hear about your focus questions, your procedure, your data, your analysis, and your conclusions. This is a 25 pt. class grade. All students must be involved in planning the presentation, but not all students need be presenters. I expect you to make use of PowerPoint to enhance your presentation.

COPPER SULFATE

There will be a 10-pt. grade on this based on your lab book: I expect to see the focus questions, the procedure, your individual team data and A completed reflection. Anything else, such as notes on the calculations or class data, is optional.

Procedure Notes:

Mass out the copper (II) sulfate for each trial into 250 mL erlenmeyers. Add roughly 100 mL of tap water and dissolve. You may speed up the dissolving process by heating the solution on a hot plate, but the solution should be at room temp. before proceeding. If the solution is too hot, the iron will rust. Add premassed iron to the copper (II) sulfate solutions. Stir until the reaction is complete (it may take 5-10 minutes). Identify the products & excess reactants of the reaction qualitatively.