[aft]

regarding single displacement and 'activity series' of metals:

i know that a given metal will displace any metal below it and thus, i am to believe that Al (aluminum) should displace Zn (zinc) in Zn(NO₃)₂ and Fe (iron) in Fe(NO₃)₂.  (All are single displacement reactions)  

The experiment was simply dropping a sample of each metal into each solution and record the results.  Because [Al] should displace [Fe] and [Zn], there should be a visible chemical change of some sort.  For example, when [Al] displaces [Cu] in CuCl₂, a precipitate forms.  HOWEVER, nothing happens visibly when [Al] is dropped into Fe(NO₃)₂ solution and Zn(NO₃)₂ solution.  

[Al] should displace [Fe] and [Zn] because [Al] is higher up in the activity series.  

I'd appreciate if anyone could give me an explanation about why there wasn't a visible reaction when [Al] was dropped into Fe(NO₃)₂ and Zn(NO₃)₂.  

Thank you for your *delete me*!

[xiankai]

Al metal forms a oxide layer when exposed to the air. This oxide layer of Al2O3, is highly impervious and unreactive and thus prevents reactions with the pure Al metal itself.

as for why the Al2O3 can react with the CuCl2, its because there's a double displacement reaction, where the precipitate is undoubtedly CuO.

[aft]

ahhhh....interesting... i actually thought about the possibility that it had something to do with the environment but never would have guessed oxidization...

thanks a bunch!!!