Now the answer which is clearly no. The rust will crumble away under the influence of water or wind or anything else rubbing against the iron. Therefore, the iron object will lose not only the oxygen that it has taken into itself, but also the part of the iron which has combined with oxygen. So the material made of iron, when it rusts, loses weight. The whole piece crumbles into red dust eventually. This is very serious, of course, for it means that the object loses its strength. And if an iron and steel bridge were allowed to decay in this fashion, it would soon break. That is one reason why such a bridge is painted to protect the iron from the air.