Achemical reaction between iron atoms and oxygen molecules can only occur if

Here is the full statement: A chemical reaction between iron atoms and oxygen molecules can only occur IF THERE ARE EFFECTIVE COLLISIONS BETWEEN THE PARTICLES OF THE TWO ELEMENTS.

Explanation:

Chemical reaction involves the re-arrangement of the particles that are present in the reacting substances. During the course of reaction, the particles of reactant are broken down and rearrange to form the products. For a chemical reaction to occur, the particles of reactants must be broken down and they must undergo effective collision. Effective collision between the atoms of iron and oxygen will give rise to the product, which is hydrated iron (lll) oxide. Without collision, chemical reaction will not occur and the product will not be formed.

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