In the balanced equation 4fe + 3o2 = 2fe2o3 how many atoms of iron (fe) are reacting with every three molecules of oxygen (o2)?

This balanced equation shows us the ratios of reactants and products, so for every 3 oxygen molecules, we see that 4 iron atoms react as well. The answer is 4.

Copper, silver, aluminum, cobalt, chromium, mercury