Quote:
Originally posted by 454Casull
Isn't iron oxide the product of oxidation between iron and oxygen? That is also what people call rust, right?
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That's right. The oxygen doesn't come from the water, but in fact comes from atmospheric oxygen dissolved in the water. This is why an iron object partially submerged in water will show the most rust forming at a short distance below the surface of the water. This is where the dissolved oxygen concentration is highest.
I've seen very clean iron rust in just a few minutes from water vapor in the air. Heating the iron to evaporate any liquid on the surface just caused it to rust faster. The heat accelerated the chemical reaction. Also, hot air can hold more water vapor than cold air. That's why the air is so humid in the summer and so dry in the winter.