Question

when octane or dodecane reacts with oxygen to form water and carbon dioxide, what fundamental step must happen to the reactant molecules before the product molecules can be formed?

Explanation:

This is a chemistry (subfield of Natural Science) question about chemical reactions. In a chemical reaction, before products are formed, reactant molecules must undergo bond breaking (specifically, the reactant molecules' bonds need to break so that atoms can rearrange to form product molecules). For the combustion of octane/dodecane (hydrocarbons) with oxygen, the reactant molecules (hydrocarbon and O₂) must first have their bonds broken. The covalent bonds in octane/dodecane (C - C and C - H bonds) and O₂ (O = O bonds) break, allowing the atoms (C, H, O) to recombine into H₂O and CO₂. The fundamental step is the breaking of bonds in the reactant molecules (bond dissociation) to form atoms or reactive intermediates that then form products.

Answer:

The reactant molecules (octane/dodecane and oxygen) must undergo bond breaking (the bonds within the reactant molecules must break) so that the atoms can rearrange to form the product molecules (water and carbon dioxide).