4Fe + 3O2 → 2Fe2O3 <or> The chemical formula for rust is Fe2O3. Rust is formed when iron reacts with oxygen in moist air. The following chemical equation represents the reaction: 4Fe + 3O2 → 2Fe2O3. Water is necessary for the oxidation reaction to occur and to facilitate transport of the electrons.
Francium has the largest atomic radius.
Answer:
The answer is "The First choice".
Explanation:
The whole question can be found in the file attached.
The water vapor inside the air freezes thru the entrance of its nitrogen. This is because liquid nitrogen has a very low temperature and seems to be sufficiently cold to condensed and freeze the steam of water. At air pressure, it has a boiling temperature of -196°C. Freezing the skin producing freeze or cold burns can be associated with direct contact.
Because pure silicon is a perfect semiconductor.
For room temperature, it rarely conducts, you can search for the threshold temperature, the characteristic equation is fairly complicated.