Question

What reaction would take place if hot tugsten was surrounded by air? explanation pleaase! gcse fundamental ideas in chemistry:)

Answer 1

A oxydation-reduction reaction would occur since the contains oxygene wich is a reactive gas. Therefore, Tungsten oxyde would be formed. Tungstene will loss most of its properties so it woul no longer conduct electricity and become brittle wich explains why light bulbs burn.

Answer 2

You'll note tungsten (W) is on the left side of the Periodic Table. That tends to make it a pretty good reducing agent, which means it is easily oxidized in general. In this case, W will react with O2 in the air to form WO3.

However, many metals, tungsten among them, will form "passivating layers" of oxide on their surfaces when exposed to atmospheric oxygen. These layers of metal oxide will protect the underlying metal from further oxidation, so that the full reactivity of the metal isn't seen in bulk metals. If you grind them up into powder, the full reactivity will emerge. In fact, this is the basis for the famous thermite reaction, in which by grinding up reactive metals (iron and aluminum) you can expose their full reactivity and get a very vigorous oxidation reacting going.

Iron is a weird exception to this rule, because iron oxide (Fe2O3) has a very different crystal structure than iron itself. What that means is that the surface oxidation, once it forms, won't stick well to the underlying iron, and will tend to flake off, exposing the metal to further oxidation. This is why iron rusts away, even though other metals don't. It's not that iron is more reactive -- it is not -- but because its oxidation layer peels off.