When oxygen (O) reacts with iron (Fe), it produces rust (Fe2O3). In a closed system, how much oxygen must react with 120 grams of iron to produce 580 grams of rust?

Explanation:

Here, I show you why it is not possible to produce 580 grams of rust with 120 grams of iron.

A. Molar masses of the substances:

B. The chemical equation is:

     4Fe   +   3O₂   →   2Fe₂O₃

How many grams of iron are there in 580 grams of rust (Fe₂O₃) ?

1. Convert the mass of Fe₂O₃ into number of moles:

2. Calculate the number of moles of Fe in 3.6320 mol of Fe₂O₃

There are 2 moles of Fe per mole of Fe₂O₃:

3. Calculate the mass of 7.2640 moles of Fe:

Thus, 120 grams of Fe is too little to produce the mentioned amount of rust; you need about 406 grams of Fe to produce 580 grams of rust.

pure substance: iron,copper

impure substance: water,charcoal