[MrPopo]

In a balanced equation, so two diatomic molecules of hydrogen, and one diatomic molecule of oxygen, creating two molecules of hydrogen.

I have to make a model of the reaction, so how would the reactants react to form water? Would it just be heat that accelerates the speed of the molecules, and when they collide they form two molecules of water?

Also, how do the two water molecules affect each other? Do they have to be in a preferred position, such as a hydrogen of one water molecule pointing to the oxygen of the other molecule? Does this apply to the hydrogen and oxygen molecules as well?


Thanks in advanced

[Schrödinger]

I can't help you much with your model, but I can tell you something about that last paragraph of your post.

Indeed, molecules of water tend to be associated through Hydrogen bonding. See http://en.wikipedia.org/wiki/Hydrogen_bond.

But I think there will be no such 'association' of H₂ and O₂  molecules. This is simply because you need distortion in electronic clouds of atoms to induce polarity and hence the attraction between centres of opposite charges. But in a molecule of H₂  or O₂ , the electronegativity of the constituent atoms is the same(since the atoms are the same). Hence there is no distortion in electronic clouds in H2 or O2. That is, there is no atom that can pull the shared pair of electrons towards itself in these molecules.
 
The only attraction you will probably find between these gas molecules(H₂ and O₂) is Van der Waals forces.

[MrPopo]

Thanks for the help so far, but I'm still really confused about the model, I've made two H2s and an O2, which makes two H2Os. Now I sort of understand the positioning of the water molecules, but I'm worried that my diatomic hydrogens and oxygens will mess up my project.

[NaOH]

This is what happens in the combustion of hydrogen

 
                2H₂  +  O₂     2H₂O