Confirming equations by experiment (1)

The reaction of iron with copper(II) sulfate

We know from the reactivity series that iron is more reactive than copper, and so should displace the copper from its compounds. However, iron forms two series of compounds - one containing the iron(II) ion and one containing the iron(III) ion. The purpose of this experiment is to carry out a gravimetric analysis in order to deduce which iron compound is formed in this reaction. The two possible equations are:

1.	Fe(s) + Cu²⁺(aq) ® Fe²⁺(aq) + Cu(s)

2.	2Fe(s) + 3Cu²⁺(aq) ⇒ 2Fe³⁺(aq) + 3Cu(s)

We shall weigh out exactly 0.01 moles of iron powder (0.56 g) and react it with excess copper(II) sulfate solution. If equation 1 is correct we would expect to obtain 0.01 moles of copper (a 1:1 ratio), but if equation 2 is correct we would expect to obtain 0.015 moles of copper (a 2:3 ratio). Watch the video and deduce which equation is the correct one. Check your conclusion here.

Video - the reaction of iron with copper(II) sulfate