Question

A high temperature reaction vessel is charged with 0.5860 mol of iron powder and 35.1 L of oxygen gas at STP.

4Fe(s) + 3O2(g) yields 2Fe2O3(s)

After the reaction vessel is cooled, and assuming reaction goes to completion, what volume of oxygen remains?

Answer 1

Answer:-

Mole of Fe= 0.5860 mol

volume of oxygen gas at STP= 35.1 L

As we know that at STP the volume occupied by a gas = 22.71L

thus, mole of oxygen gas at STP = Volume of oxygen gas at STP/ 22.71

= 35.1/22.71

= 1.5456 mol

As given 4Fe(s) + 3O₂ (g) ----> 2Fe₂O_3(s)

Dividing the above equation by 2

2Fe(s) + 3/2O_2(g) -------> Fe₂O₃(s).

As from the equation

2 moles of Fe reacts with 3/2 mole of O₂ to give one mole of Fe₂O₃

Thus, let x mole of O₂ reacts with 0.5860 moles of Fe

0.5860/2=x/3/2

0.5860*3=4*x

x= 1.758/4

x=0.4395 mol

so remaining moles of oxygen gas= 1.5456-0.4395

= 1.1061 mol

so amount of oxygen gas remained= 1.1061*22.71

= 25.1195 L